canonical linking rules: forward versus reverse linking in ......canonical linking rules for mapping...

Cognition, 51 (1994) 29-72 OOlO-0277/94/$07.00 0 1994 - Elsevier Science B.V. All rights reserved.

29

Canonical linking rules: forward versus reverse linking in normally developing and specifically language-impaired children

Heather K.J. van der Lely Department of Psychology, Birkbeck College, University of London, Malet Street, London WClE

7HX, UK

Received September 2, 1991, final version accepted June 17, 1993

Abstract

Canonical linking rules for mapping thematic roles with syntactic functions were studied. Three experiments were undertaken to investigate the nature of productive forward linking (from semantics to syntax) and productive reverse linking (from syntax to semantics). I proposed that reverse linking, in contrast to forward linking, requires more detailed specification of the syntactic structure; that is, a syntactic representation which specifies each particular syntactic frame and all the argument positions within that frame. Six specifically language-impaired children (aged 6;l to 9;6) were matched on language abilities to 17 younger, normally developing children (language age 3;l to 6;6). In Experiment 1 -forward linking - the children were shown the meaning of a novel verb and had to describe the event using the novel verb. Experiment 2 - a comprehension task - required acting out sentences containing the newly learned verbs. In Experiment 3 - reverse linking - the children were told a sentence with a novel verb and had to act out its meaning,

I would like to thank Dorothy Bishop, Harald Clahsen, Richard Ingham, Rita Manzini, and Neil

Smith and in particular Steven Pinker and two anonymous reviewers for their comments and

interesting discussions on a previous draft of this paper. I am also grateful to the staff of Glebe Infant

school and Moorlands day nursery and to the speech and language therapists who assisted me in

finding appropriate subjects for this investigation.

The basis of this research was undertaken in partial fulfilment for a PhD degree at the University of

London, and was supported by a competition studentship from the Economic and Social Research

Council. I thank Margaret Harris and David Howard who supervised this work. A version of this

paper was presented at the 17th annual Boston University Conference on Language Development,

October 1992, Boston: Mass. The preparation of this paper was supported by a post-doctoral fellowship from the British Academy.

SSDZ 0010-0277(93)00577-T

30 H.K.J. van der Lely I Cognition 51 (1994) 29-72

assigning thematic roles on the basis of the syntactic frame. Group and individual analysis generally revealed no significant differences between the specifically language-impaired children and the language age control children in Experiments 1 and 2, but a significant difference was found for Experiment 3. The normally developing children showed a good use of productive forward and reverse linking. The specifically language-impaired children demonstrated good productive forward linking but were significantly worse at reverse linking. An interpretation of the data, showing differences in the syntactic representation required for forward versus reverse linking, can account for the findings. I propose that a deficit in the area of “government” or “locality” which underlies c-selection and specifies the syntactic relationship between constituents can account for the data from this study and the data from previous investigations of specifically language-impaired children.

Introduction

Linguists and psychologists have recently shown increased interest in a group

of children who are “specifically language impaired” (SLI). SLI children are

characterized by severe problems in the development of language comprehension

and expression, but are normal in non-linguistic cognitive and motor develop-

ment, hearing, and emotional behaviour. The nature of the linguistic disorder and

the underlying deficit in these children can provide insights into the mechanisms

of language acquisition which could not be possible from investigations into

children developing normally.

This study investigates the “canonical linking rules” which have been hypoth-

esized to play an important role in the learning of verb-argument structure (e.g.

Bowerman, 1990; Pinker, 1989). Canonical linking rules refer to the regular

relationship found in the majority of languages between thematic roles, such as

agent and patient, and syntactic functions such as subject and direct object. For

example, if a child knows that a verb involves an agent and a patient, she can

infer that those arguments are expressed as the grammatical subject and object,

respectively. The canonical or default mapping between particular thematic roles

and particular syntactic functions may apply in the absence of information to the

contrary.

Canonical linking rules can operate bidirectionally; from semantics to syntax

(forward linking) and from syntax to semantic (reverse linking). The study aims

to provide insight into the nature of the forward versus reverse linking pro-

cedures, focusing on the syntactic nature of the linking rules when they are used

in a forward as opposed to a reverse direction. By investigating linking in a

population of SLI children these two mapping mechanisms can potentially be

distinguished. Do individual SLI children differentially use forward linking and

H.K.J. van der Lely I Cognition 51 (1994) 29-72 31

reverse linking and what are the characteristics which may explain this‘differential

use?

Canonical linking rules

In this section I shall first discuss linking rules and how they may facilitate

language acquisition. I shall then consider the possible syntactic nature of the

linking rules when they are used in a forward versus reverse direction.

Linking rules are the regular ways in which thematic roles (such as agent and

patient) are mapped onto syntactic functions (e.g., subject, object) (Bowerman,

1982; Bresnan, 1982; Jackendoff, 1972; Pinker, 1984). Particular thematic roles

are associated with a verb and form part of its semantic structure. The linking

rules, or correspondences between thematic roles and syntactic functions (e.g.,

agent-subject), may be innate (Grimshaw, 1987; Pinker, 1984, 1989) or learned

early in the process of language acquisition (Bowerman, 1990; Foley & Van Valin,

1984). In either case the linking regularities facilitate language acquisition.

There has been much discussion about what constitutes the “canonical” or

default mapping. The earlier approach characterized canonical linking in terms of

two interrelated hierarchies: one for thematic roles and one for syntactic functions

(Bresnan, 1982; Fillmore, 1968; Jackendoff, 1972; Pinker, 1984). The thematic

role of a predicate, which was the highest on the hierarchy (e.g., agent), was

linked to the highest available syntactic function (e.g., subject). The next highest

thematic role (e.g., theme/patient) was linked to the next available highest

syntactic function (e.g., object) and so on. The more recent approach does not

use the notion of thematic roles being in a fixed list but defines them as argument

positions within the semantic representation of a verb’s meaning (Dowty, 1991;

Jackendoff, 1987; Levin, 1985; Pinker, 1989; Rappaport & Levin, 1988). The

theory makes explicit the properties of the event that the verb refers to; for

example, agentive, causal and temporal. Traditional thematic labels like “agent”

and “patient” can serve as mnemonics for some of the argument positions

(Gropen, Pinker, Hollander, & Goldberg, 1991b) and will be used as such in this

paper. For example, “agent” is defined as the first argument of CAUSE and

ACT, “patient” is the second argument of CAUSE and ACT, “theme” is the first

argument of GO and BE, “location” is the second argument of BE, and goal is

the second argument of TO, etc. (e.g., Pinker, 1989). For each thematic role (or

more accurately, each argument position) a linking rule maps it to a syntactic

function; for example, agent is linked to subject, patient is linked to object,

theme is linked to subject if that function has not already been assigned,

otherwise to object, and location to oblique object.

The use of a verb in a different syntactic frame causes differences in meaning.

For example, the passive is represented as a circumstantial state (BE) in which


the circumstance of the theme is the event or state corresponding to the active

verb form (Pinker, 1989). Therefore, the semantic representation and the

argument structure differ for corresponding active and passive verbs. If the child

can identify the appropriate semantic properties and thus the arguments of a

predicate, in the absence of any conflicting information, she can apply the

particular linking rule to map each argument onto the appropriate syntactic

function (Pinker, 1989). This paper will be based on this more recent theory of

canonical linking. All the syntactic frames in which a verb can occur reflect the

semantic representation and canonical linking. However, the term “non-canoni-

cal” linking will be used in this paper to refer to any mapping that does not

represent the default semantic-syntactic relationship: for example, an agent (first

argument of CAUSE) mapped onto the direct object in a transitive active

sentence would be a non-canonical mapping.

Linking rules may facilitate language acquisition in several ways. Pinker

(1984), Berwick (1985) and others have hypothesized that children use knowledge

of thematic roles and the linking rules to “bootstrap” themselves into syntax; that

is, “semantic bootstrapping” (Pinker, 1984), which facilitates the development of

phrase structure rules.

The semantic cues may also be used by children to express the meaning of a

new predicate in an utterance without previously hearing it in a sentence. For

example, when learning a new verb the child can determine the thematic roles of

the noun arguments on a non-linguistic basis and then, with the use of the

canonical linking rules, map the arguments onto the default syntactic functions.

This may be seen as “productive” learning of verb-argument structure (Pinker,

Lebeaux, & Frost, 1987). Previous research has shown that young children of 3-5

years of age are sensitive to the semantic-thematic roles associated with a

predicate and will canonically link these roles onto syntactic functions productive-

ly (Gropen, Pinker, Hollander, Goldberg, & Wilson, 1989; Gropen et al., 1991a;

Pinker et al., 1987). The use of semantic cues and forward linking will be

investigated in this study.

Another way in which linking rules may facilitate language acquisition is when

syntactic cues are used in conjunction with the linking rules to help learn the

meanings of verbs (Gleitman, 1989, 1990; Golinkoff, Hirsh-Pasek, Cauley, &

Gordon, 1987; Landau & Gleitman, 1985; Naigles, 1990; Naigles, Gleitman, &

Gleitman, 1992). The syntactic cues may be used in more than one way. First, by

attending to the verb’s subcategorization frame the child can predict aspects of its

meaning (Landau & Gleitman, 1985). For example, Naigles and Kako (in press)

conclude that the transitive frame specifies a sense that one character is affecting

another.

Landau and Gleitman (1985) have coined the term “syntactic bootstrapping”,

which refers to attending to sets of subcategorization frames associated with a

verb stem. This procedure may facilitate learning verbs by narrowing down the

possible meanings shared by all of the stem’s syntactic entries. It is a contentious


issue as to the extent syntactic bootstrapping can facilitate and is needed to learn

a verb’s meaning (see Pinker, 1993). However, hearing a verb in one syntactic

frame may give some information about the verb’s semantic structure (e.g., the

number of arguments and type of arguments), although it cannot reveal anything

about the core meaning content of the verb (e.g., the movement defined as

“hitting”). The use of syntactic cues to infer thematic roles associated with a verb

has been referred to as reverse linking (Pinker, 1989) (i.e., syntactic to semantic

mapping). Pinker has suggested that reverse linking may be particularly important

in learning verbs which undergo certain syntactic alternations such as the passive

and locative. This paper focuses on the semantic information that may be derived

from hearing a verb in one syntactic frame; that is, reverse linking.

The nature of the syntactic representation used with the linking rules is not

clear. However, I shall attempt to specify the syntactic representation which may

be required for linking rules to be used in a forward and reverse direction. In

forward linking in which semantic cues are used to map from thematic roles to

syntactic structures, Gleitman (1989) has suggested that a “one-to-one” mapping

may be used. Thus, one thematic role (e.g., agent) may be mapped onto one

noun phrase (NP) (e.g., first NP) without recourse to the other thematic roles and

syntactic functions associated with the predicate. A “basic” syntactic representa-

tion of the phrase structure may be sufficient to facilitate the appropriate

canonical linking relationship. For example, when the child is presented with a

new verb, providing the child has already worked out that the agent of a causative

event corresponds to the first NP in the sentence and the patient corresponds to

the second NP, etc., she may not require any further syntactic knowledge of the

structural syntactic relationships between the constituents. However, a syntactic

representation of the linear order of an NP in relation to the verb may not be

sufficient if the syntactic cues are to be used to infer particular thematic roles.

This is because of the many-to-few mapping between thematic roles and syntactic

functions; for example, if something is the agent of a transitive active verb it is

sure to be the subject in nominative accusative languages, but if something is the

subject of a transitive active verb it need not be an agent (it could be a recipient,

as in “receive”; a location, as in “contain”; and so on).’ Pinker (1989) indicates

that it is not completely clear how reverse linking should work at all given that

there are many sets of thematic roles that are consistent with many surface

frames. However, he suggests that reverse linking would have to involve

comparisons between the surface form of a sentence and some kind of schema or

core for common linking patterns abstracted from sets of individually acquired

verbs.

My proposal is that, in order to activate the appropriate schema and to

constrain the possibilities of which thematic role to map onto the first NP (in the

‘I am grateful to Steven Pinker for reminding me of this.


absence of any semantic information), the child needs to identify each and every

argument position within a particular syntactic frame. The structural relationships

between the constituents in a syntactic frame enable each NP to be uniquely

identified; for example, subject-NP versus object-NP. Therefore, the child

requires a syntactic representation of each particular syntactic frame (e.g.,

transitive active frame) in which the NPs are differentially identified. Merely

identifying one NP and the verb would not provide sufficient syntactic cues for the

child to activate the appropriate linking schema and constrain the many possible

mappings of thematic roles to the NP. A non-specified NP could as easily be

linked to a patient/theme as to an agent thematic role. I propose that the more

detailed syntactic representation of the syntactic frame and the argument

positions within that frame are needed for reverse linking but not necessarily

forward linking. This structural syntactic representation can be linguistically

characterized by the c (categorical)-selectional properties of a verb (Chomsky,

1981) and syntactic government which differentially “marks” the NPs in a

sentence by specifying their positions.

Specifically language-impaired children

The majority of SLI children previously investigated have been found to have

an expressive deficit which is most pronounced in the phonological and morpho-

grammatical aspects of language (Bishop, 1992; Clahsen, 1989; Gopnik, 1990;

Leonard, 1982, 1989, 199,l). Recent studies have highlighted consistent deficits in

SLI children’s comprehension of sentences (Bishop, 1979, 1982; Connell, 1986;

Precious & Conti-Ramsden, 1988; van der Lely, 1990; van der Lely & Dewart,

1986; van der Lely & Harris, 1990). The most significant findings to be revealed

by these data are the following:

(1) Children previously classified as suffering from an expressive disorder as

well as those with a receptive language disorder are usually impaired in their

comprehension of sentences (Bishop, 1979).

(2) The deficits have been found in interpreting complex sentences, such as

passive and embedded sentences (Bishop, 1982; van der Lely & Harris, 1990) and

also simple active transitive sentences (van der Lely and Dewart, 1986; van der

Lely and Harris, 1990).

(3) Particular difficulties have been found in comprehending semantically

reversible sentences in which word order is particularly important in signalling the

relationship between the syntactic and thematic roles. The SLI children’s

performance in these studies has been characterized by a high proportion of

“word order errors”; that is, errors in sentences where correct assignment of


thematic roles to syntactic functions such as subject and object is reversed,

(Bishop, 1982; van der Lely & Dewart, 1986; van der Lely & Harris, 1990).

(4) Finally, SLI children’s sentence comprehension deficits have been found in

a variety of sentences (transitive, locative and dative) (van der Lely & Harris,

1990). These studies have all included control groups of children matched on

receptive language abilities of single word vocabulary. In some studies the SLI

children were also matched to the control children on production of morphologi-

cal forms and naming vocabulary. Thus, the SLI children had a disproportionate

language deficit in the comprehension of reversible sentences. However, not

everyone agrees that SLI children do have problems assigning thematic roles.

Gopnik and Crago (1991) did not find that their group of SLI children (who were

characterized by a genetic familial aggregation) were impaired in this area of

language. This may be because of the different methodology used by Gopnik and

Crago, or because there is heterogeneity in the population. That is, subgroups of

SLI children exist which have different linguistic characteristics. The extent to

which these subgroups are related is far from clear. This study investigates the

subgroup of SLI children who show grammatical deficits in expression and

comprehension of language.

There have been few studies which have explored the processes involved in

sentence comprehension in SLI children. If we are to go beyond merely

describing their language difficulties and provide further insight into their disorder

it is evident that further investigations are needed into the processes involved in

sentence comprehension. This study aimed to establish if SLI children’s superficial

difficulty with word order in comprehending reversible sentences could be

attributed to faulty “mapping mechanisms” for learning verb-argument structure.

In this study, three experiments were conducted to investigate the use and

nature of semantic and syntactic cues and the canonical linking rules to learn the

mapping properties of novel verbs in normally developing and SLI children.

Experiment 1 investigated the productive use of forward linking (semantic to

syntactic mapping). Experiment 2 tested the children’s comprehension of the

newly learned verbs in Experiment 1, and Experiment 3 investigated the

productive use of reverse linking (syntactic to semantic mapping). The experi-

ments investigated a subgroup of six SLI children with a disproportionate

grammatical impairment in the comprehension and expression of language in

relation to their other language abilities, such as single word vocabulary. Because

of the possibility of heterogeneity in groups of SLI children, the study investigated

individual subjects’ patterns of responses as well as group data.

The questions to be addressed were: (a) Do SLI children’s responses demon-

strate the productive use of forward linking to map semantic-thematic roles onto

syntactic structures? (b) Do SLI children comprehend the newly learned novel

verbs when they are presented in active and passive sentences? (c) Do SLI


children demonstrate the productive use of reverse canonical linking to map

syntactic functions onto thematic roles for novel verbs presented in sentences? (d)

Does the SLI children’s ability to perform these tasks differ from that of children

matched on some measures of language abilities?

It was predicted that (a) if the SLI children’s deficit is with the linking rules

themselves (either because the lacked the appropriate (innate) semantic-syntactic

knowledge or they had not learned the canonical relationship between semantic

and syntactic roles) then they should be impaired in all three tasks; (b) if the SLI

children’s deficit lies in the use of semantic or syntactic cues to facilitate learning

the lexical properties of verbs then they should be impaired in Experiment 1 or 3,

respectively; (c) if the SLI children’s deficit lies in recalling or using a newly

learned representation of verbs, then their performance would be impaired in

Experiment 2, but not in Experiment 1 or 3. Such a deficit could be indicative of a

more general learning problem for linguistic knowledge.

EXPERIMENT 1: FORWARD LINKING

In Experiment 1 the children were shown the meaning of a novel verb using an

acting out procedure; for example, the experimenter said “This is voozing”, as

she made a toy girl jump up and down on a toy boy’s back. The children were

then asked to say what was happening using the new verb to see if they would say

“The girl is voozing the boy”, or “The boy is voozing the girl”. The experiment

was designed to see if the children identified thematic roles from two types of

events. One corresponded to a causative transitive event; that is, an event

involving an agent and a patient/theme. The second was a causative event

involving agent and patient/theme thematic roles and also a goal thematic role;

for example, a car was made to tap a lorry sideways to a train. For the purpose of

this paper I shall refer to this second event as the “locative” event or scene. As in

some previous studies (Pinker et al., 1987; Gropen et al., 1989, 1991b) I used

here invented novel verbs, for which there was no exact equivalent verb in

English. This would prevent prior semantic and syntactic knowledge from

facilitating performance in the experimental task. In comprehension tasks it is

possible that linking rules could be used in the reverse direction based on the

syntactic cues provided by the sentence. Therefore, to avoid this possibility,

expressive language was used as a measure of productive forward linking. Probe

questions, used to elicit the responses, were syntactically neutral in that no

specific role could be attached to a particular toy based on the syntactic structure

of the question; for example, “Tell me about the boy”. There were 10 verbs and

three probe questions for each verb.


Method

Subject details

Two subject groups participated in the experiments: a group of SLI children

and a group of younger children matched on receptive and expressive language

abilities.

Specifically language-impaired children

There were six SLI children - five boys and one girl - selected from a larger

group that had been under investigation for the previous 2 years. The children

were characterized by a disproportionate deficit in their grammatical abilities in

the expression and comprehension of language.

The original selection criterion was as follows. Firstly, all the children had been

identified by speech and language pathologists and educational psychologists as

having persistent difficulties with language comprehension; that is, their scores fell

more than 1.5 s.d. below the expected normal range of abilities on some

standardized tests - and they were undergoing their education in language units.*

The selection of the SLI children was based on the set of criteria proposed by

Stark and Tallal (1981). To provide a uniform measure of language abilities and a

criterion for inclusion in the group, two tests of comprehension and two of

expressive language abilities were administered. Only children who had a mean

comprehension age of at least 6 months lower than their chronological or mental

age (whichever was the lower) and a mean expressive language of at least 12

months below their chronological or mental age were included in the group (Stark

& Tallal, 1981).

The non-verbal abilities of all the SLI children had been assessed by education-

al psychologists using standardized IQ tests (e.g., WISC-R) and fell within the

normal range. In addition, two tests of non-verbal abilities were administered to

provide a mental age score on which to base the children’s language age. The

Block design from the British Abilities Scale (Elliott, Murray, & Pearson, 1978)

and the Draw-A-Man test (Harris, 1963) were used. Only children who attained

an IQ of above 85 on both tests were included. This original group’s language

ages ranged from 2;8 to 5;5 (yearqmonths), and their chronological ages ranged

from 4;5 to 7;lO. The raw scores from the tests for the original selection of the

group have been previously reported (van der Lely & Harris, 1990) and,

therefore, further details will not be given here. All the children met the criterion

of normal development with respect to hearing, neurological development, socio-

emotional behaviour and development as described by Stark and Tallal (1981).

*That is, a small class, specializing in language remediation

38 H.K.J. van der Lely i Cognition 51 (1994) 29-72

The six SLI children in this study were selected to be representative of the

original group. Therefore the severity of their original language impairment and

their rate of progress on standardized tests of language over the previous 2 years

varied. The SLI children were reassessed on the same four standardized tests. The

choice of these tests was determined by their previous use for research purposes

and reliability in identifying SLI children (Bishop & Adams, 1989; van der Lely &

Harris, 1990), rather than any adherence to theoretical notions on which the tests

were based. The two tests of comprehension were the Reynell Developmental

Language Scales (Reynell, 1977) (a general test of understanding) and the British

Picture Vocabulary scale (Dunn, Dunn, Whetton, & Pintillie, 1982) (a more

specific test of comprehension of single word vocabulary). The two standardized

measures of expressive language were the Grammatical Closure Subtest from the

Illinois Test of Psycholinguistic Abilities (ITPA) (Kirk, McCarthy, & Kirk, 1968)

(a test of grammatical morphology) and the Expressive Vocabulary from the

British Ability Scales (Elliott et al., 1978). Characteristically, the SLI children

performed better on the vocabulary tests than on the test of morphology. To

provide the reader with an estimate of their language abilities, an overall language

age was calculated from the four language tests. However, this language age is

merely a guide and caution is expressed in taking this measure too literally as the

SLI children perform relatively well on some tests but show severe impairments

on other tests which tap different language abilities. Their language ages ranged

from 3;7 to 6;5. Their chronological ages ranged from 6;l to 9;6. Table 1 provides

a summary of subject details; further details of the language scores for each of the

children on the four tests can be found in Appendix A.

As is characteristic of SLI children generally, some of the SLI children in this

study performed within normal limits on some of the tests. However, the

language impairment of all six SLI children was of such severity they were still

undergoing their education in language units.

Language age control group

Each child in the SLI group was individually matched to three language control

children on the basis of individual scores from three standardized language tests.

Table 1. Subject details for the SLI children and LA controli

Subject group Chronological age Language age

Mean Range Mean Range

SLI children 7;2 6;1-9;6 5;4 3;4-6;5 (N=6) LA controls 5;2 3;4-6;6 5;3 3;1.5-6;6 (N = 17)


The tests were the British Picture Vocabulary Scale (BPVS), the Grammatical

Closure Subtest from the ITPA, and the Expressive Vocabulary from the British

Ability Scales (BAS). The tests were administered to 55 children whose

chronological ages approximated the language ages of the SLI children. The

control children came from an infant school and private day nursery in a rural

city. Seventeen matched control children (nine boys and eight girls) whose raw

scores on at least two of the three language tests were the nearest to those of their

assigned SLI child were selected from the sample. Two of the SLI children, OC

and SJ, who had identical overall language ages, shared one control child. The

scores of all the language age (LA) controls fell within the normal limits on the

three language tests. Analysis revealed no significant differences between the LA

controls and the SLI children on the raw scores of the three standardized tests of

language abilities (for the BPVS, 421) = 0.15, for the Grammatical Closure,

ITPA subtest, 421) = 0.35, and for the Expressive Vocabulary, BAS, 421) =

0.51). Therefore the LA control group were matched to the SLI children on all

three tests of language ability. The mean language ages for the LA controls

ranged from 3;1.5 to 6;6. A summary of the LA control subject details can also be

found in Table 1, and further details of the raw scores for each test in Appendix

A. Additional information of the matching procedure can be found in van der

Lely and Howard (1993).

Design and materials

Experiment 1 was designed to test the productive use of canonical forward

linking, mapping semantic roles to syntactic functions. Subject group (SLI

children and LA controls) constituted a between-subject variable in the experi-

ment. There was one within-subject variable; that is, the semantic structure of the

scene (transitive or locative).

Ten verbs were invented for which there was no exact equivalent meaning in

English. Five of the verbs corresponded to transitive activities. That is, the

activity involved two participants: one which could be construed semantically as

an agent; and the other a patient/theme thematic role. The remaining five verbs

corresponded to the so-called locative activities. These activities involved the

movement of two toys (an agent and patient/theme) towards a toy which could be

construed as the goal of the activity. For example, a car (agent) moving sideways

tapping a train (patient/theme) sideways to a lorry (goal). The phonological form

of the 10 verbs, which corresponded to a CVC sequence, and a description of

their meanings, is summarized in Table 2. All the verbs were potentially

semantically reversible, in that either toy participating in the activity could take

on either thematic role. Selection of the toys was carefully controlled to maintain


Table 2. Experiment 1. Forward linking: list of novel verbs and a description of their meaning

Transitives

1. Mooking

2. Tiving

3. Kalling

4. Geeping

5. Voozing

X slides down the back of Y.

X bounces Y on his head, holding Y upside down.

X pushes Y over, with front of vehicle.

X pushes Y, head to head while lying on floor.

X jumps up and down on Y’s back.

Locatives

6. Mipping

7. Zecking

8. Dassing

9. Fiming

10. Bozing

X backs into Y and pushes it backwards to 2.

X taps Y sideways to Z.

X carries Y on her head to Z and puts Y on Z’s head.

X carries Y sideways across her back

and bounces with Y to Z.

X pulls Y to Z with a rope looped around the wheels of

X and Y, and attaches Y to Z’s wheels.

this semantic neutrality. Therefore, for each scene the selected toys were either

all people or all transport toys (see list below).

Eight small toys were used in the Experiment. Four toys corresponded to

people (man, lady, girl, boy) and four to transport (car, lorry, train, tractor).

Procedure

The children were tested individually in a small room. The experimenter sat

opposite the child at a small table. The eight toys were placed on the table, with

the people and transport toys grouped separately. The child was asked to name

the toys. Following successful naming of the toys, it was explained to the child

that she would be told a “funny” word and then the toys would show her what it

meant. The funny word was attributed to an unusual looking puppet who was

going to watch what was happening and make sure the examiner showed the child

the correct meaning. The puppet was going to see if the child had learnt the word.

The order of presentation of the 10 verbs was randomized, but with a transitive

scene occurring first. The child was told the first verb, which was presented as a

gerund, and asked to repeat it at least twice, with the examiner repeating it at

least three times. An example of the teaching and experimental phase for one of

the verbs is described below. The example involves the verb tiving, which has the

meaning “X bounces Y on his/her head whilst holding Y upside down”.

Demonstration (a): the toy man is made to walk towards the toy woman. The

experimenter said “This is tiving” as she demonstrated the meaning of the verb;


that is, the man was made to hold the woman’s legs and he bounced the woman

up and down on her head.

Demonstration (b): this involved the same toys as the first demonstration,

except that the thematic role the toys were made to take on was reversed.

Therefore the woman was made to take on the agent role and the man the

theme/patient role.

Demonstration (c): two different toys were selected for this demonstration;

that is, the boy was made to perform the agent role and the girl the theme role.

The procedure was otherwise identical to the first demonstration.

Testing phase: the toys in demonstration (c) were used in the testing phase, but

the thematic roles the toys were made to take on were reversed. That is, the girl

was made to tiv the boy. Three identical demonstrations were made in the testing

phase. Each demonstration was accompanied by one of three probe questions

which were presented in the following order: (i) Tell me/the puppet what’s

happening. (ii) Tell melthe puppet about the girl (agent). (iii) Tell melthe puppet

about the boy (patient/theme). If the child responded to the first question with

only a gerund, or did not respond at all, then a further puppet was introduced to

try to make the required response pragmatically more plausible. (This puppet hid

in a bag, as he was very shy, but he wanted to know all about what was

happening!) The session was recorded on a portable tape recorder for later

transcription.

Scoring

Utterances were transcribed for each subject from the audiotape. Appendix C

gives an example of the responses for three SLI children and three LA controls to

one of the novel verbs. The three possible responses to each verb were coded in

the following way:

(a) Use of the novel verb: from the 30 possible responses, each response was

coded as to whether the novel verb or an alternative verb (which partially

described the scene) had been used for the five transitive verbs and five locative

verbs.

(b) The responses to the transitive and locative scenes were analysed separ-

ately and according to whether a novel verb or other verb had been used. The

responses were coded into the type of syntactic frame in which the verb was used.

For the transitive scenes these were: verb-only response (e.g., tiving/VP);

intransitive response (e.g., The boy is tivinglNP VP); transitive response (e.g.,

The boy is tiving the girflNP VP NP). For the locative scenes an additional

category was used in which the location-goal was also encoded in the response

42 H. K.J. van der Lely I Cognition 51 (1994) 29-72

(e.g., The car bozes the lorry to the train/NP VP NP PP). This will be referred to

as a locative response.

(c) Canonical linking: responses in which the novel verb had been used for

each question were analysed to establish the number of thematic roles that

conformed to a “canonical” or “non-canonical” mapping of semantic-thematic

roles to syntactic functions. Canonical linking, as discussed in the Introduction,

was based on the definition put forward by Levin (1985), Dowty (1991),

Jackendoff (1987), and Pinker (1989). So, for example, if the agent of the

causative event was mapped to the subject-first NP it was counted as canonical,

but if it was mapped to the object-second NP it was counted as non-canonical.

Further description of canonical linking is given below.

There were three possible argument structure types that were appropriate to

describe the transitive scenes: (1) unergative intransitive; (2) transitive active; (3)

transitive passive. An additional argument structure type was possible for the

locative scenes: (4) a transitive with oblique object containing to. Noun phases and preposition phases were coded as canonical on the basis of

word order when an active sentence was used. However, the morphology was

taken into account when a passive utterance was used. The intransitive responses

were scored as canonical if the agent was assigned to the subject. The child

obtained a score of 1 for each canonical intransitive response. The transitive

active responses were scored as canonical if the toy taking the agent role in the

demonstration was assigned to the subject/first noun phrase, and the patient/

theme to the object/second noun phrase. The transitive passive responses were

scored as canonical if the theme was assigned to the subject and the agent to the

oblique object (preposition phrase) (after Pinker et al., 1987). If a response was

ambiguous when both word order and morphology were considered then a strict

criterion was adhered to and the response was scored as non-canonical. An

example of this ambiguity is clearly shown by one of MP’s responses to question

3: The girl is kalling by the boy. On the basis of word order alone this response

would have been scored as canonical. However, on the basis of morphology, the

use of the gerund and the preposition make it ambiguous as to MP’s intention.

The child obtained a score of 2 for each canonical transitive active or passive

response. However, short passive sentences (The girl is mooked) scored only 1.’

The scoring for the transitive with oblique object responses (prepositional

locatives) followed the criterion set out above. In addition, if the goal thematic

role was assigned to the oblique object and was morphologically marked by the

preposition to or another appropriate preposition such as up to, it was taken to be

canonical. For the locative scenes, if all three possible arguments were expressed

‘This conservative criterion was used as it is possible that the short passive responses could have

been adjectival rather than verbal passives. Therefore it cannot be assumed that the second argument is “absorbed” by the passive morphology. (cf. Borer & Wexler. 1987).


and corresponded to canonical linking, the child scored 3. Responses for the

locative scenes which consisted of three noun phrases (e.g., The cur mips the train and the lorry) were coded as transitive utterances, providing the first two noun

phrases conformed to a canonical linking of the agent to the subject and the

theme/patient to one of the following noun phrases. The “goal” thematic role

was not differentiated and therefore did not contribute to the child’s score. Table

3 provides the details from all of the responses containing the novel verbs for the

six SLI children according to the scoring criterion.

Results

Analysis of group data

The initial analysis assessed the frequency of novel verb responses. The

percentage use of the 10 novel verbs was calculated for each child from the three

responses for each verb. A 2 x 2 (Group X Verb type) ANOVA was used to

investigate these data. It can be seen from Table 4 that both groups used the

novel verbs, rather than an alternative known verb, for the majority of their

responses. Analysis revealed no significant effects for group, F( 1,21) = 1.13,

p = .30, verb type, or the interaction. Thus, the groups did not differ in their use

of the novel verb for the transitive or locative scenes. Further analyses were

carried out on the novel verb responses.

The main analysis for forward linking was based on responses to questions 1

and 2 for the transitive and locative scenes. Responses to question 3 were not

included owing to some ambiguity in some of the responses (see scoring above).

From the maximum of 20 novel verb responses, the total number of canonically

expressed thematic roles in the intransitive, transitive and locative syntactic

frames were tallied. A canonical intransitive response scored 1, and a transitive

and locative response 2 and 3, respectively (see scoring section for further

details). It can be seen from this procedure that the total forward linking score

was sensitive to both the mapping relationship and the number of thematic roles

expressed in the sentences. The maximum score for the 10 responses for the

transitive scenes was 20, whereas for the 10 responses for the locative scenes it

was 30. The proportion of canonically expressed thematic roles was calculated for

each child from the maximum possible scores for the two scene types. Thus, a

score of 50% for the transitive scenes would represent 10 thematic roles expressed

canonically, whereas the same proportion (50%) for the locative scenes would

represent 15 thematic roles expressed canonically. The mean proportion scores

for the two subject groups for the transitive and locative scenes can be found in

Table 4. This mean proportion score is a conservative estimate of the use of

forward linking as the proportion was based on the maximum possible score.


Table 3. Experiment 1. Forward linking: coding of the novel verb responses for the six SLI children

Transitive scenes Locative scenes

Response type Response type

Verb Intrans. Trans. Verb Intrans. Trans. Locative

only only

Subject: MP

Question 1 Canonical 2 4

Non-canonical 2 1


Non-canonical 1


Non-canonical 4 1

Response type: total 1 14 15

Subject: OC

Question 1 Canonical 5 5 Non-canonical

Question 2 Canonical 5 3 1 Non-canonical

Question 3 Canonical 4 1 Non-canonical 5

Response type: total 15 12 2

Subject: SJ

Question 1 Canonical 2 1 2 1

Non-canonical 1

Question 2 Canonical 1 3 Non-canonical

Question 3 Canonical 1 Non-canonical 1 1

Response type: total 2 3 2 3 6

Subject: AS


Non-canonical

Question 2 Canonical s 3 2

Non-canonical


Non-canonical



Table 3. (Continued)

Transitive scenes Locative scenes

Response type Response type

Verb Intrans. Trans. Verb Intrans. Trans. Locative only only

Subject: AW

Question 1 Canonical 3 3 1

Non-canonical 1


Non-canonical 1 1

Question 3 Canonical 3 2 1

Non-canonical 1 1 2


Subject: DL

Question 1 Canonical 3 2 1 Non-canonical

Question 2 Canonical 3 2 1 2 Non-canonical


Non-canonical 1 1


Table 4. Experiment 1. Forward linking: mean scores for the novel verb responses for the SLI children and LA controls

SLI children LA controls

Mean % (SD) Mean % (SD)

Transitive scenes

Novel verb usea

Number of canonically linked

thematic roles (max. = 20)b

83.33 (19.02) 78.91 (19.06) 53.33 (23.38) 46.18 (32.38)

Locative scenes

Novel verb usea

Number of canonically linked

thematic roles (max. = 30)h

83.50 (13.65) 64.91 (34.41) 42.20 (16.02) 36.27 (30.03)

“Responses to questions 1, 2 and 3.

bResponses to questions 1 and 2.

Therefore, to score 100% all the children’s responses would have had to contain

the novel verb and the maximum number of possible thematic roles (two for each

of the two responses for the five transitive verbs and three for the two responses

for each of the five locative verbs). Approximately 80% of the children’s


responses contained the novel verb and, although appropriate, the children’s

responses did not always express the maximum number of thematic roles.

The effects of subject group and verb type (transitive or locative) were

investigated using a 2 x 2 ANOVA (Subject group x Verb type). It can be seen

from Table 4 that there was a lower proportional mean score for the locative

verbs than for the transitive verbs, reflecting the increased semantic-syntactic

complexity for these verbs. However, the main effect of verb type failed to reach

the significance level, F(1, 21) = 3.47, p = ,076. Surprisingly, the SLT children’s

mean proportional scores showed that they expressed more thematic roles

canonically than the LA controls for both the transitive and locative scenes.

However, the main effect of subject group was not significant, F(1, 21) = 0.27,

p = .607, nor was the Group x Verb type interaction, F(1, 21) = 0.01. The initial

analyses indicated that the SLI children and the LA controls were performing in a

similar way. The children expressed thematic roles of novel verbs demonstrated in

transitive and locative scenes canonically and productively in utterances. The two

groups also expressed a similar number of canonical thematic roles in their

responses.

Further planned analyses were undertaken to establish whether differences in

the performance of the SLI children and LA controls could be found. The first of

these investigated whether the two groups’ responses reflected a similar propor-

tion of argument structures types. From the 1.5 possible responses (i.e., the

responses to the three questions for each of the five verbs) for the transitive

scenes, the proportion of intransitive and transitive responses using the novel

verbs was calculated for each child. The proportion of locative responses for the

locative scenes was also calculated. Canonical and non-canonical assignment of

the thematic roles was not taken into account as this had been assessed in the

previous analysis. Table 5 shows the mean proportion of responses for the

transitive and locative scenes according to the sentence type used. One-way

(Group x Sentence type) ANOVAs were carried out on the data from the

Table 5. Experiment 1. Forward linking: mean proportion of sentence types for

the transitive and locative scenes for the two subject groups

Sentence

response type

SLI children

Mean % (SD)

LA controls

Mean % (SD)

Transitive scenes (max. score = 15) Intransitive 32.22

Transitive 43.33

Locative scenes (max. score = 15) Intransitive 30.00

Transitive 42.22

Locative 5.54

(35.17) 13.33 (17.64)

(39.26) 40.39 (31.93)

(28.83) 5.49 (8.24)

(30.60) 31.76 (37.38)

(10.65) 9.80 (17.81)


transitive and the locative scenes. Analysis of the transitive scenes revealed no

significant difference between the groups in the proportion of transitive responses

used, F(1, 21) = 0.03. The proportional scores for the intransitive responses

showed a skewed distribution and were therefore transformed by taking the

square root. The analysis was carried out on these transformed data. Although

the SLI children showed a higher mean proportion score in comparison to the LA

controls for the intransitive responses, the difference was not significant, F(1,

21) = 1.72, p = .204.

Analysis of the locative scenes revealed no significant differences in the

proportion of locative responses, F(1, 21) = 0.30, or transitive responses, F( 1,

21) = 0.38. The proportional scores for the intransitive responses were trans-

formed to control for a skewed distribution. Unlike the previous analyses, and

despite the high standard deviation, the SLI children were found to use a

significantly higher proportion of intransitive responses than the LA control

children, F (1, 21) = 9.18, p = 0.006.

Individual subject analysis

Because of the reported heterogeneity of SLI children as a group, the

individual pattern of performance for each child was analysed on the basis of a

“consistently canonical response”. For the purpose of this analysis, if the response

to each question contained at least one canonically linked thematic role and no

non-canonical linked thematic roles, it was counted as a canonical response. This

criterion was used as pragmatic reasons may have caused the children not to

express all the possible thematic roles in their responses.

The number of canonical responses were calculated for each child for the

transitive and locative scenes (see Table 3 for the SLI children’s individual novel

verb responses). Responses to question 3 were not included in this analysis owing

to the known difficulty some SLI children have with morphology and in producing

and comprehending passive sentences. Therefore, the scores were based on the 20

responses from questions 1 and 2 for the 10 verbs. The criterion for a consistently

canonical response was set at 14 or more out of 20, p = .057, cumulative

binomial. This criterion was a conservative one as the children did not always use

the novel verb, and when they did they sometimes did not express any thematic

roles.

Five of the SLI children passed the criterion. One SLI child, SJ, did not pass

the criterion, scoring 10 canonical responses out of the possible 20. This was

largely due to a greater number of real verb responses, rather than the novel

verb, and some elliptical verb-only responses. Five of the 17 LA controls also did

not pass the criterion. This was due to elliptical verb-only responses, made by

some of the younger LA control children. Selection of appropriate control


children in studies investigating SLI children is always a problem. The most

appropriate control group is language-matched controls for investigations of

language abilities. This has the disadvantage in that the control children are

younger and their non-linguistic cognitive abilities are less mature than those of

the SLI children. It is possible that for the LA control children the task demands

in Experiment 1 exceeded their development of cognitive abilities, and that this

accounted for the elliptical responses made by some of the youngest children.

The data were scrutinized for non-canonical responses to questions 1 and 2; for

example, where the demonstration showed a boy taking an agent role and the girl

a patient role, who were assigned to an object and subject, respectively, in an

active sentence. None of the LA controls made any non-canonical responses. Two

of the SLI children (MP and AW) made four non-canonical responses (20%) and

two SLI children (SJ and OC) made one such response (5%). This indicates that

some SLI children have a slight but non-consistent difference in response pattern

in comparison with the LA control children. It can also be seen from Table 3 that

MP made an additional five non-canonical responses to question 3. Scrutiny of the

data revealed that all of these non-canonical responses were due to ambiguity

between word order and morphology; for example, The lady is fiming by the man. Thus, they may be attributed to his difficulties with morphology and hence with

forming passive sentences. Whilst it is interesting to note these morphological

errors, further discussion of these errors falls outside the scope of this paper.

Discussion

Throughout the results, generally, the SLI children were not found to be

performing significantly differently from the younger children who were carefully

matched on the comprehension and expression of single word vocabulary and

expressive morphology.

The SLI children and LA controls were able to observe a scene acted out with

toys, identify the participants and their appropriate thematic roles, and verbally

express these relationships in a sentence. Although the mean proportion of

thematic roles expressed in the responses are lower than those found when real

verbs are used or when novel verbs are modelled in a sentence (e.g., Pinker et al.,

1987), the mean proportions are still much greater than zero. The proportions of

canonical thematic roles expressed by the children in this experiment (approxi-

mately 40-50%) are comparable to those found in previous experiments in which

unmodelled novel verbs were elicited in sentences (Gropen et al., 1989). The

results indicate that both the normally developing and SLI children were using

forward, canonical linking productively to map from semantic-thematic roles

onto syntactic structures. The findings support previous research which has

indicated that normally developing children can use canonical linking rules to


express events containing novel verbs without having heard the verb in a syntactic

context (Gropen et al., 1989, 1991a,b). Analysis of the different sentence types

(intransitive, transitive or locative sentences) expressed by the children, when

using the novel verbs, showed that the SLI children and LA controls did not differ

in their use of locative or transitive syntactic frames. Importantly, these data

indicate that the similar scores obtained for the canonically linked thematic roles

by the SLI and LA control children were not achieved for different reasons; for

example. the SLI children producing fewer transitive novel verb responses but

making fewer errors. The SLI children used more intransitive sentences for both

the transitive and locative scenes with the difference reaching significance for the

locative scenes. It is likely that this increased proportion of intransitive responses

can account for the SLI children’s overall slightly higher number of canonically

linked thematic roles.

The group analysis was generally supported by the individual subject analysis.

This showed that five of the SLI children used forward canonical linking

consistently; that is, 80% or more of the time. One SLI child used forward

canonical linking in only 50% of her responses. This lower forward linking score

was due, primarily, to a greater use of real verbs, rather than the novel verbs. The

few non-canonical responses to questions 1 and 2, which were used by four SLI

children, could indicate that they were performing differently from the LA

controls. (None of the LA controls showed any non-canonical responses.) Three

of the eight non-canonical responses used by two SLI children occurred for the

novel verb mooking. It is possible that the agent role was not as salient in the

demonstration for this verb as it was for some of the other verbs. In addition, the

influence of semantic argument structures of previously (conservatively?) learned

verbs which share semantic similarities may have detrimentally influenced the SLI

children to a greater extent than their younger language peers. The following

example, which has some semantic similarities with mooking, illustrates this

possible conflict: in the situation where a girl gives a boy a “piggy-back”, the girl

is seen as the agent although it may be that the boy approaches the girl and climbs

onto her back, whereas for the verb “ride” the opposite is true. In view of the

evidence that SLI children can and do consistently assign thematic roles canoni-

cally to syntactic structures this would seem to be a plausible explanation for these

non-canonical responses.

EXPERIMENT 2: COMPREHENSION OF NOVEL VERBS

To assess how the children had encoded the semantic structure of the newly

learned novel verbs, the expressive responses for each verb in Experiment 1 were

followed by a comprehension task. The 10 novel verbs from Experiment 1 were

each presented in reversible active and passive sentences, according to the verb’s


prescribed meaning: for example, The lorry is zeked by the car to the train (prepositional locative). The child’s task was to act out with small toys the

meaning of the sentence containing the newly learned verb. This task could tap

the previous use of productive forward linking and a current use of reverse linking

to facilitate mapping between the thematic roles and syntactic functions.

Method

Subjects

The same group of subjects who participated in Experiment 1 participated in

Experiment 2.


For each of the 10 verbs created in Experiment 1, six reversible sentences were

constructed for the comprehension task for Experiment 2. There were three

active and three passive sentences. The six sentences for each verb were written

onto a presentation card in a random order, except that the first sentence was

always an active one. The eight toys used in Experiment 1 were used in this

experiment.

Procedure

The six questions testing comprehension for each verb immediately followed

the presentation of the corresponding verb in Experiment 1. The acting out

procedure was explained simply to the child, who was asked to show the puppet . . for example, the car tivs the train (question 1). The six questions for

each novel verb were presented in the same random order for each child. A

description of the child’s response was recorded by the experimenter on prepared

test sheets.

Scoring

An acting out response was scored as correct if it conformed to a canonical

linking (as defined in Experiment 1) between all of the syntactic functions in the

sentence and the thematic roles the toys were made to take on. Errors were

assigned to the following categories:

(4

(b)

(4

(d)


Non-canonical; that is, when the correct toys were selected but the

thematic roles demonstrated did not correspond to a canonical linking; for

example, the subject in an active sentence was assigned to a patient

role.

Semantic error: (i) verb; (ii) noun; that is, either an incorrect action was

demonstrated, or the child selected an object that was not mentioned in

the sentence.

Omission: one or more thematic roles were omitted in the acting out of the

sentence.

Ambiguous;

on were not

that is, where the thematic roles the toys were made to take

clear.

Results

Group analysis

The total number of responses that corresponded to canonical linking was

calculated for each child. Table 6 shows the mean scores for these data for the

two subject groups. A mixed design 2 x 2 X 2 ANOVA was used to investigate the

data. There was one between-subject variable: subject group (SLI children, LA

controls); and two repeated measures: sentence type (transitive and locative) and

word order (active, passive).

The main effects for sentence type and word order were significant, F( 1,

21) = 17.72, p < ,001, and F(1, 21) = 12.76, p = .002, respectively. As can be

seen from Table 6, this reflected the higher scores for the transitive than for the

locative sentences, and for the active than for the passive sentences.

Although the SLI children generally performed worse than the LA controls the

main effect of subject group did not reach the significance level, F(1, 21) = 3.30,

p = .084. None of the interactions were significant, F(1, 21) <2.74, p > .113, in

all analyses. The SLI children and the LA controls performed at a low level on

the passive locative sentences, and the SLI children also performed at a low level

Table 6. Experiment 2. Comprehension: mean canonical acting out responses to the sentences by the SLI children and LA controls

Sentence type SLI children (max. = 15) LA controls (max. = 15)

Mean (SD) Mean (SD)

Transitive actives 11.33 (1.03) 14.29 (1.53) Transitive passives 10.16 (3.97) 12.53 (3.77)

Locative actives 7.33 (5.60) 10.47 (4.89)

Locative passives 6.67 (5.32) 7.34 (5.37)


on the active locative sentences (see Table 6). To clarify the results and establish

whether the children were performing above chance level, and to take account of

possible heterogeneity in the SLI group, an individual subject analysis was carried

out.


To investigate individual subjects’ pattern of responses the data from each

child were recoded to derive a pass/fail score (i.e., an above/below chance

performance) for each sentence type. The criterion for a consistent response was

set at 12/15 for the transitive sentences, p = .035. For the locative sentences the

criterion was set at 6/15, p < .05. The criterion for the locatives was based on the

possibility that the three nouns in the sentence could potentially take on any of

the thematic roles. Therefore, the probability of a single correct response for the

locative sentences was estimated to be p = .167. (In the event, if the stricter

criterion of 12/15 had been used it would not have made a difference to the

results.) Table 7 summarizes these data. Analysis of the numbers of children from

each subject group passing or failing the criterion for each set of sentences was

carried out using the Fisher exact test. No significant differences between the two

groups were found, confirming the findings from the group analysis.

Although on each of the individual pass/fail analyses there were no significant

differences between the groups, the percentages of SLI children passing the

criterion was lower than that of the LA controls for each sentence type. It was

possible that across the four sentence types the SLI children were performing

below the LA controls. A meta-analysis was carried out to test for this possibility.

The exact probability from each of these tests was combined using the

following formula: ~22~ = -2~ log,; Pi will be distributed on x2(2 d.f.) (Howell,

Table 7. Experiment 2. Comprehension: numbers of SLI and LA control children reaching the criterion for the active and passive sentences for the two verb types

Sentence type SLI children LA controls

Fail (%) Pass (%) Fail (%) Pass (%) p

Transitive active 2 (34) 4 (66) 2 (12) 15 (88) ,231

Transitive passive 3 (50) 3 (50) 4 (24) 13 (76) .226 Locative active 2 (34) 4 (66) 4 (24) 13 (76) ,638

Locative passive 3 (50) 3 (50) 7 (41) 10 (59) ,708


1987).4 The result from this combined test was still not significant (xi = 7.5

p > .25).

Discussion

The results of the test of the comprehension of active and passive sentences

containing the novel verbs showed that the SLI children’s performance did not

differ significantly from the LA controls’ performance. This finding was confirmed

by the analysis of the pass/fail data based on individual children’s above/below

chance performance. The increased syntactic and semantic complexity of the

passive and locative sentences can account for the overall worse performance on

these sentences by the SLI children and the LA controls. Only one SLI child (AS)

showed a consistently correct response to all four sentence types. One of the SLI

children (DL) did not show a consistently correct interpretation on any of the sets

of sentences. Two out of three of DL’s LA-matched controls also failed to

respond correctly on any of the sets of sentences. Thus, DL’s failure may be

attributed to his general level of language abilities.

The results of these data indicate that at least five of the SLI children were able

to recall the semantic lexical representation of the newly learned verb. It is likely

that this lexical representation of the verb was based on the previous use of

forward linking. The findings further indicate that the children were able to learn

the syntactic properties of a verb by using the canonical linking rules in a forward

direction, and could retrieve the semantic properties associated with a lexical

entry. The pass/fail data revealed that only some of the SLI children can use

productive rules for mapping with more complex structures such as the passive or

locative sentences. The SLI children who were able to interpret the passive

sentences may still have been able to rely largely on their previous representation

of the newly learned novel verb: that is, if the SLI children processed the passive

participle and know something about its stative qualities this could have been

sufficient to assign the first NP to the patient/theme role, without further syntactic

processing of the sentence.

It is possible that the children used the syntactic cues from each sentence and

applied the linking rules in the reverse direction to help them assign the syntactic

functions to thematic roles. It is not clear whether the SLI children were relying

solely on their previous representation of the verb, based on forward linking, or

whether they were also using reverse linking to facilitate mapping. A reliance only

on the newly formed representation of the verb could account for the poorer

‘Strictly speaking this assumes that the samples are independent.


performance of the SLI children in Experiment 2. Experiment 3 aimed to clarify

whether SLI children could use reverse linking productively.

EXPERIMENT 3: REVERSE LINKING

For Experiment 3, involving syntactic to semantic mapping, a new set of novel

verbs was presented in a total of 24 reversible active and passive transitive

sentences and active locative sentences. Passive prepositional locative sentences

were not included in this experiment owing to the low (chance) level of

performance on these sentences in Experiment 2. The children’s task was to

assign appropriate thematic roles to the grammatical functions; to make up an

event that went with the novel verb in the sentence; and to act out with toys a

possible meaning. For example, on hearing the sentence The girl voozes the boy, the child was to make the girl (agent) do something to the boy (patient). A

productive use of reverse linking was required to complete the task. This task

investigated the use of only syntactic cues to assign thematic roles in the absence

of an observable event. Therefore, in contrast to the previous two experiments,

there were no semantic cues available to constrain the possible meanings of the

verbs in this task.

Method

Subjects

The same subjects participated in Experiment 3 as in the previous two

experiments.


A further 16 novel CVC verbs were invented. For eight of the novel verbs

reversible active sentences were created; for example, The girl kals the boy. The

same eight verbs were used to create eight reversible passive sentences. These

sentences consisted of the same subject and object for each verb, but with passive

morphology, thereby changing the thematic roles of the grammatical functions

(e.g., The girl is kalled by the boy). The remaining eight novel verbs were used to

construct eight reversible active prepositional locative sentences with a final to


prepositional phrase (e.g., The cur rits the train to the lorry). A full list of the

sentences can be found in Appendix B.

The nouns used in the sentences corresponded to seven of the eight toys used

in Experiment 1. The tractor was omitted, as it may not have been so familiar to

some of the children. The nouns were counterbalanced across the sentences, so

that they occurred with approximately equal frequency in subject, object and

oblique object positions.

The eight toys used in the previous two experiments were also used in this

experiment.

Procedure

The experimenter sat opposite the child at a small table in a quiet room. The

eight toys were placed in front of the child. Prior to presentation of the test

sentences, the child was encouraged to play with the toys and to demonstrate

novel actions that the toys could be made to perform. Examples of possible

actions were demonstrated by the experimenter. For instance, the toy girl was

made to bend a sitting person over; or the car was made to repeatedly tap the top

of the lorry. The child was then told that it was her turn to make up or guess what

she thought the sentence with the “funny word” could mean and to show the

puppet by acting it out with the toys. It was stressed to the child that the

sentences could mean lots of things and that there was not a strict “right” or

“wrong” answer. However, they were to try very hard to make up a possible

meaning. Sentence presentation was random, except that a transitive active

sentence was presented first. All 24 sentences were presented in one session. A

description of the acted out responses was recorded at the time of testing. If the

experimenter was unsure of the child’s intentions as to which toy was (for

example) the agent, the child was asked to show the experimenter the meaning of

the sentence again and the stimulus sentence was repeated. If the thematic roles

assigned to the toys were still unclear the response was scored as ambiguous. In

the event, there were few ambiguous responses which required a repetition and of

those which did very few remained ambiguous. For the majority of responses

there was little possibility for misinterpreting the child’s intention as to which

thematic role the toys were taking on. The children tended to make the agent

very active and the patient/theme very passive; for example, making the boy

jump up and down on the back of the girl who was lying on the table, or making

the car hit the lorry off the table. An example of a set of responses for three SLI

children and three LA controls to one of the sentences can be found in Appendix

D.


The child’s acting out responses were scored as correct when the thematic roles

the toys were made to take on conformed to a canonical reverse linking. The

criterion used for canonical linking was the same as that set out in Experiment 1;

for example, for the active sentences the subject was assigned to an agent role,

the object to a patient/theme role, and for the locative sentences the oblique

object was assigned to a goal role. For a correct response all the syntactic

functions mentioned in the sentences had to be assigned canonically. Other

responses were coded into the same categories as those in Experiment 2: (a)

non-canonical, (b) semantic, (c) omission, (d) ambiguous. For further details see

scoring section, Experiment 2.

Results

Group analysis

The mean correct scores (i.e., acting out responses which corresponded to

canonical reverse linking) are presented in Table 8. A 2 x 3, Subject group x

Sentence type (active transitive, passive transitive and active locative sentences)

ANOVA design was used to investigate these data.

The main effect of subject group was significant, F(1, 21) = 9.57 p = .006,

which reflected the worse scores for the SLI children in comparison to the LA

controls. The main effect of sentence type was also significant, F(2, 21) = 12.39

p < .OOl. The Group X Sentence type interaction was not significant.

Planned comparisons provided further insight into the performances of the two

groups to the different sentence types. For the LA controls no significant

difference was found between their performance on the transitive and locative

sentences. However, a significant difference was found between the active and

passive transitive sentences, F(1, 16) = 6.75 p = ,019, which reflected the higher

scores for the active sentences.

For the SLI children, both comparisons were significant. Their performance on

Table 8. Experiment 3. Reverse linking: mean canonical acting out responses to the sentences by the SLI and LA control children

Sentence type SLI children (max. = 8) LA controls (max. = 8)

Mean (SD) Mean (SD)

Transitive active 5.50 (0.84) 7.29 (1.44)

Transitive passive 3.67 (1.50) 5.16 (2.79)

Locative active 2.33 (2.25) 5.53 (3.04)


the locative sentences was found to be significantly below that of the transitive

sentences, F(1, 5) = 13.97, p = .013. Their performance on the passive transitive

sentences was also significantly below that of the active transitive sentences, F(1,

5) = 7.86 p = .038.


As in Experiment 2, to clarify the results and consider individual subjects’

pattern of responses and possible heterogeneity in the groups, the data were

recoded into a pass/fail score (above/below chance performance). The children

were credited with consistently producing a canonical response if they scored at

least 7/8 canonical responses (p < .035) for the active and passive transitive

sentences. The probability of a canonical response for the locative sentences was

again estimated to be p = .167. Therefore, the criterion was set at 418 (p = .031).

The number of subjects in each group who were able to interpret consistently

each set of sentences canonically was calculated (see Table 9). None of the SLI

children reached the criterion for the two sets of transitive sentences. Fisher exact

tests revealed significant differences between the groups for the active sentences,

p < .OOOl, and for the passive sentences, p = ,022. A marginally significant

difference was found for the locative sentences, in which two SLI children passed

this less stringent criterion (p = .056). These results showed that significantly

fewer SLI children than LA control children consistently used reverse linking,

mapping from the syntactic structure to a semantic structure, on the three

sentence types.

The analysis of errors made by the SLI children revealed that nearly all of the

errors fell into the non-canonical category. An appropriate event was invented by

the children involving the toys mentioned in the sentence; the thematic roles were

compatible with the syntactic frame; but the assignment of which thematic role

corresponded to which toy did not correspond to the canonical linking.

In Experiment 2, although there was no significant difference between the two

groups’ performance, the SLI children’s performance was lower than that of the

Table 9. Experiment 3. Reverse linking: numbers of SLI and LA control children whose acting out responses reached the canonical response criterion Sentence type SLI chiidren LA controls

Fail (%) Pass (%) Fail (%) Pass (%) p

Transitive active 6 (100) 0 (0) 2 (22) 15 (88) .OOOl

Transitive passive 6 (100) 0 (0) 8 (47) 9 (53) ,022

Locative active 4 (66) 2 (33) 4 (24) 13 (76) .056


LA controls. It is important to establish whether the SLI children and LA control

children were performing differently across Experiments 2 and 3. Both experi-

ments used the same acting out comprehension paradigms. However, only reverse

linking could be used in Experiment 3 and no semantic constraints were available,

whereas forward and reverse linking could be used in Experiment 2 and semantic

constraints were available from the newly learned lexical representation. Further

analysis of Experiments 2 and 3 together is warranted to help rule out alternative

explanations based on the task demands.

Analysis of Experiments 2 and 3

Based on the percentage of correct scores for each experiment a further 2 x 2

(Subject group x Experiment) ANOVA was carried out to investigate these data

(see Table 10).

The main effect of subject group was significant, F(1, 21) = 4.46, p = ,047,

which reflected the lower scores for the SLI children. The main effect of

experiment was not significant, F(1, 21) = 0.89. However, the Group X

Experiment interaction approached significance, F(1, 21) = 3.87, p = .062. Simple

effects analyses revealed that the two group’s performance in Experiment 2 was

not significantly different, F(1, 21) = 1.65, p = .214, whereas in Experiment 3 a

significant difference was found, F(1, 27)5 = 7.13, p = .013. This confirmed that

the SLI children’s performance was significantly worse than the LA controls’

performance in Experiment 3, but not in Experiment 2.

Analysis of the LA controls’ performance across the two experiments revealed

no significant difference, F(1, 16) = 0.52, p = .23, one-tailed, indicating that they

had a similar level of performance on Experiments 2 and 3. In contrast, analysis

of the SLI children’s performance across the two experiments revealed a

significant difference, F(1, 5) = 4.23, p = .026, one-tailed. This reflected the

lower scores obtained on Experiment 3.

The result of these analyses together all indicate that the SLI children were

Table 10. Mean proportion of canonical responses for Experiments 2 and 3 for the SLI and LA control children

SLI children

Mean % (SD)

LA controls

Mean % (SD)

Experiment 2 59.15 (24.33) 73.22 (22.11)

Experiment 3 47.90 (16.62) 77.18 (25.31)

‘Because a pooled error term is used the degrees of freedom associated with the pooled error term

were adjusted to remove bias in the test (Satterthwaite, 1946).


performing significantly worse on Experiment 3 in comparison to both their own

performance in Experiment 2 and in comparison to the LA controls’ performance

in Experiment 3.

Discussion

The results of the performance of the SLI children in Experiment 3 clearly

contrasted with their performance in Experiment 1. Analysis of the mean correct

scores showed that the SLI children were significantly worse at using the syntactic

cues to derive thematic roles based on reverse linking. Both groups of children

found assigning thematic roles to passive transitive sentences more difficult than

to active transitive sentences. This finding concurs with previous research into

normal language development which has shown the particular difficulty of

comprehending known verbs in reversible passive sentences (Bever, 1970; de

Villiers & de Villiers, 1973) and the lower performance with production and

comprehension of passive sentences with novel verbs (Pinker et al., 1987). The

SLI children, unlike the LA controls, performed significantly worse on the

locative sentences than the transitive sentences. This suggests that the SLI

children were affected to a greater extent by the syntactic complexity of the

locative sentences.

The pass/fail data supported and clarified the findings of the group analysis.

This analysis showed that the significantly worse performance of the SLI children

in comparison to the LA controls was evident for all three sentence types. The

data were surprising in that nane of the SLI children reached the criterion for a

consistently correct response on the active or passive transitive sentences, and

only two SLI children (AS and AW) reached the criterion on the locative

sentences. It can be recalled that the criterion for the locative sentences was set at

4/8. However, it is possible that parsing the locative sentences into phrases would

enable the “goal” thematic role to be assigned separately from the verb.

Jackendoff (1989) argued that nouns in prepositional phrases are assigned their

thematic role-argument structure by the preposition and that they are merely

“licensed” to co-occur with a particular verb. Therefore, the assignment of

thematic roles for the so-called locative verb would be a binary choice between

the subject and object. If this were so, the appropriate criterion for a consistently

correct response should have been 7/8 for the locative sentences as well as the

transitive sentences. The two subjects from the SLI group, AS and AW (who

scored 4/8 and 6/8, respectively), would not have reached this more stringent

criterion, although 8/17 (47%) of the LA controls would have reached the

criterion. It is also interesting to note that the LA controls who failed to interpret

the locative sentences generally interpreted the oblique object as an additional

theme or omitted this third argument. However, they assigned the subject and


object noun phrases canonically to thematic roles. No such pattern emerged for

the majority of SLI children. These children’s errors appeared to be unsystematic

with any of the grammatical functions being assigned any thematic role.

Analysis of the Group x Experiment (Experiments 2 and 3) interaction

approached significance. Analysis of the simple effects revealed that the SLI

children performed significantly worse on Experiment 3 than on Experiment 2,

whereas the LA control children showed a similar level of performance across the

two experiments. The analysis confirmed that the SLI children’s performance was

significantly worse than the LA controls’ performance on Experiment 3 but there

was no significant difference in their performance on Experiment 2. The

difference in the performance of the two groups in these two acting out tasks is

useful in helping to identify the underlying reasons for the SLI children’s deficit in

reverse linking revealed by this study, and will be taken up in the general

discussion below.

The SLI children’s chance level of performance as measured by the individual

analysis (see Table 9) in a task involving canonical reverse linking is particularly

striking when considered in relation to previous research investigating the use of

syntactic cues and canonical linking rules to infer aspects of the meaning of a

verb. Gleitman (1989), using a looking preference task, found that young children

of 3 and 4 years were heavily guided by the syntactic frame when presented with

novel sentences, with 85% of all responses showing canonical mapping. The

individual analysis of the LA control’s responses in this experiment, in which 88%

of the children reached the consistent canonical mapping criterion for active

transitive sentences, concur with Gleitman’s findings. These data support the view

that for children developing language normally, the syntax may guide the child’s

choice of interpretive options, particularly in ambiguous circumstances. In

addition, the data from this study provide evidence that the syntactic cues from a

single syntactic frame may be used in the absence of an observable scene and any

possible semantic cues, to help assign thematic roles to a verb for which they do

not have a semantic-lexical representation. In this way the syntactic cues may

constrain the possible meaning of a verb in that the verb’s meaning must allow or

“license” the particular thematic roles (as determined by the syntactic frame) in

its semantic-lexical representation. The data also indicate that this mechanism

may not be available for the SLI children.

The implications of the findings to the underlying cause of SLI in children and

the nature of forward and reverse linking will now be explored in the general

discussion.

GENERAL DISCUSSION

Two different mechanisms for mapping thematic roles with syntactic function

were investigated: the use of productive forward linking involving semantic cues


to map from semantics to syntax; and the use of productive reverse linking

involving syntactic cues to map from syntax to semantics.

Surprisingly, the use of productive forward linking and reverse linking has not

previously been investigated in a single population. It was not clear whether

individual differences would be apparent in the use of forward linking and reverse

linking. For example, would the children be able to use both mechanisms when

the context demanded their use, or alternatively, would they rely on one

particular mechanism? A good use of both mechanisms was shown by the

majority of the LA controls. This was not so for the SLI children, who showed an

impairment in the reverse linking task despite their good use of productive

forward linking. The subgroup of SLI children investigated in this study appeared

to be homogeneous in that all the children conformed to this pattern.

The data from this study showing differences between Experiments 1 and 2

versus Experiment 3 suggest that there are differences between using linking rules

in a forward versus reverse direction. These differences may account for the

particular difficulties the SLI children have with reverse linking. The data suggest

that the differences between using linking rules in a forward versus reverse

direction may be linguistic. Before I explore these issues it is important to

discount alternative explanations which arise from differences in the tasks used to

investigate forward versus reverse linking. The task differences are, first, the

demands of the production task in Experiment 1 and the comprehension task in

Experiment 3, and secondly, the non-linguistic cognitive demands of the tasks in

Experiments 2 and 3.

Experiments 1 and 3: task differences

Can the difference between the forward and reverse linking tasks be explained

by the different processes involved with producing versus comprehending a

sentence? Clark and Hecht (1983) pointed out that in language production the

child has to choose the words and structures to convey his or her own intention,

whereas in comprehension the child has to infer another person’s intentions.

Thus, one may look to find a deficit in inferential processing or, alternatively,

other processing demands incurred in comprehension but not production. How-

ever, a search for identifying processing differences between comprehension and

production is not warranted by these data and could not explain the SLI children’s

pattern of performance in this study: a different pattern of performance was

found for the SLI children in comparison to the LA controls in Experiment 2

versus Experiment 3, both of which required comprehension of sentences. In

addition, the SLI children performed significantly worse on Experiment 3 than

Experiment 2, whereas the LA controls had a similar level of performance in the

two experiments.


The role of familiarity with verbs

Another consideration is that the comprehension task in Experiment 2 was in

some ways “easier” than that in Experiment 3. It is possible that increased

familiarity and experience with the verbs in Experiment 2 is the main reason why

the SLI children did better on Experiment 2 than Experiment 3. However, the

verb was presented as a gerund in the demonstrations in Experiment 1. Thus, no

matter how many times the child was exposed to this situation the increased

familiarity would not give any indication of the assignment of the verb’s thematic

roles to particular syntactic structures. Merely being familiar with the verb and its

meaning will not provide the vital clues to improve mapping performance.

Furthermore, evidence from the analysis of the LA controls’ performance across

Experiments 2 and 3 indicates that Experiment 2 was not easier than Experiment

3. The LA controls showed a similar level of performance on both experiments

(see Table lo), with a slightly higher mean score on Experiment 3, which clearly

goes against this explanation.

Non-linguistic cognitive processing

It is difficult to see how non-linguistic demands could account for the overall

pattern of performance of the children found in this study. First the LA controls

did not generally show an inability to carry out Experiment 3, and their

performance on Experiments 2 and 3 was similar. Also, it was the SLI children

who were impaired on Experiment 3 and not the younger, and cognitively less

mature, LA control children. SLI children by definition have normal age-

appropriate non-linguistic cognitive abilities and show normal abilities on, for

example, non-linguistic hypothesis testing tasks (Kamhi, Catts, Koenig, & Lewis,

1984). Pre-experimental testing showed that all the SLI children in this study

performed within normal limits on non-linguistic performance subtests of stan-

dardized IQ tests (e.g., WISC-R); achieved an equivalent IQ score of 90 or above

on two further tests of non-linguistic abilities (van der Lely & Harris, 1990); and

the same two subject groups did not differ on extensive testing of auditory-verbal

short-term memory (van der Lely & Howard, 1993).

Forward versus reverse linking

The most likely explanation for the performance of the SLI children may be

found in the linguistic differences between using linking rules in a forward versus

reverse direction. I shall now discuss the implications of the findings for the

characterization of this subgroup of SLI children and the differences between


forward and reverse linking. The findings will then be considered in relation to

the previous findings from investigations of sentence comprehension and mor-

phology in SLI children.

First, although the SLI children were considerably worse at using reverse

linking, their relatively good performance with forward linking indicates that they

have the innate ability or have learned the canonical relationship, that is, the

linking rules, between specific thematic roles and syntactic functions. Whilst this

may be sufficient to carry out the forward linking task it does not appear that it

was adequate for the reverse linking task. At this point it may be useful to

reiterate the inherent difference between forward and reverse linking. The

difference is due to the many-to-few mapping between thematic roles and

grammatical functions. The semantic information available in forward linking

provides the necessary constraints for a one-to-one mapping between semantic

roles and syntactic functions to be sufficient to complete the task without analysis

of the overall syntactic frame and the relationship between the constituents. The

many-to-few mapping between thematic roles and syntactic functions makes this

problematic without semantic constraints for reverse linking. Crucially, for

reverse linking, I proposed that the structural relationship, established through

c-selection and involving syntactic government, is needed to identify a particular

syntactic frame, specify each argument position within that frame, and activate a

schema or core of linking patterns. Therefore, for example, the first NP in an

utterance would be identified within an SVO, active, transitive syntactic frame.

This would activate the core of linking patterns which would assign the subject-

NP to an agent thematic role only, rather than any of the other possible thematic

roles which could be assigned to a first NP in an utterance. Alternatively, in

forward linking the semantic cues provide the necessary constraints which enable

an agent thematic role to be assigned to the first NP in the utterance.

From the proposed characterization of reverse linking there are two loci (at

least) in which a deficit may cause a child to fail. First, the child may activate the

wrong schema, or may not yet have developed a schema for common linking

patterns. Alternatively, the child’s syntactic cues may contain insufficient in-

formation for identification of the syntactic frame which enables assignment of the

thematic roles canonically.

Analysis of the errors made by the SLI children in the reverse linking

experiment provide clues as to where the SLI children’s deficit may lie. If the SLI

children’s deficit was with the schema for common linking patterns, it could be

predicted that semantic errors would occur. Semantic errors involving incorrect

thematic roles being demonstrated by the SLI children rarely occurred. Such

errors would have been made if, for example, all three mentioned nouns in the

locative syntactic frame were assigned a “theme” role. This response would be

appropriate for a sentence such as The girl, the boy and the man vode, but not for

any of the syntactic structures in this experiment. Nearly all the errors made by


the SLI children were associated with a non-canonical linking. An appropriate

event was invented by the children involving the toys mentioned in the sentence.

The thematic roles were compatible with the syntactic frame. However, the

assignment of which thematic role corresponded to which toy did not correspond

to the canonical linking between the syntactic functions and thematic roles. These

data suggest that the SLI children know something about a syntactic frame

involving two NPs and a verb. This was insufficient for an appropriate schema or

core of common linking patterns to be activated; for example, the argument

structure type, “transitive”6 and thematic core “X acts on Y” (Pinker, 1989) fit

these data. However, the SLI children appear unable to analyse the particular

syntactic argument positions in the sentence and reason back from these syntactic

arguments the likely thematic roles underlying them based on the linking schema.

Thus, the SLI children’s deficit is not with the schema per se, but with the

specification of the syntactic cues which would “motivate” the canonical mapping

of thematic roles. I conclude that the SLI children have the required syntactic

representations to enable them to carry out the forward linking task but that this

is insufficient (in the absence of any semantic constraints) for the reverse linking

task.

In sum: an interpretation of the data, showing differences in the syntactic

representations required for using linking rules in a forward versus reverse

direction, can account for the performance of the SLI children. A “basic”

syntactic representation, involving analysis of the individual phrases and their

linear position in relation to the verb or overall utterance, is required for

productive forward linking. A syntactic representation which specifies each

particular syntactic frame and all the argument positions within that frame (and

thus, the relationships between the constituents) is required for productive

reverse linking. I propose that SLI children have a deficit with the syntactic

representation which specifies the relationship between the verb and the argument

positions.

There are many components which could underlie the reverse linking process

and could account for the deficit found for the SLI children. I have already argued

that non-linguistic processes cannot account for the data. The possibilities are also

constrained by previous findings characterizing SLI children’s language abilities.

One possibility is a deficit in the area of government or locality (Chomsky, 1981,

1986a; Wexler & Manzini, 1987) which underlies c-selection and specifies the

asymmetrical relationship between constituents. This proposal makes predictions

across a huge range of syntactic modules and processes in which government

provides the necessary principles and constraints. It could be predicted that a

.deficit in government would cause problems with case assignment, the distribution

“‘transitive” is used here merely to identify a NP V NP sequence, which may or may not be hierarchically organized.


of the empty category PRO, spec-head agreement, binding theory, as well as with

theta role assignment and c-selection. Other syntactic modules and principles may

be intact; for example, the X-bar module which would be able to provide

elementary hierarchical structure through lexical categorization, phrasal projec-

tions (although the governing relationship between sister elements and the

direction of it may not be syntactically defined), and s-selection and the

generalized projection principles would ensure that all lexical information was

syntactically represented. The data from this study and previous findings from

investigations into the comprehension and the expressive language abilities of SLI

children are consistent with a deficit in government. SLI children have been found

to have particular difficulties with case, gender, tense, spec-head agreement, and

c-selection (e.g., see Clahsen, 1989; Clahsen, Rothweiler, Woest, & Marcus 1992;

Fletcher, Ingham & Kirby, 1992; Leonard, 1989; Leonard, Bortolini, Caselli, &

McGregor, in press); and with theta role assignment in comprehension of

reversible sentences (e.g., Bishop, 1982; van der Lely & Harris, 1990).

The particular strengths and weaknesses in forward and reverse linking

revealed for the SLI children may explain other findings characterizing the

linguistic abilities of SLI children. The data from this study indicate that SLI

children will be particularly impaired when language learning may be facilitated

by reverse linking. SLI children may not be able to learn verb meaning

productively from the syntactic structural cues in the input utterances. A deficit in

the use of reverse linking can explain the particular difficulties SLI children have

in comprehending sentences with “known” verbs (Bishop, 1982; van der Lely &

Harris, 1990). Pinker claims that reverse linking is mandatory for learning certain

syntactic alternations such as the active-passive alternation (Pinker, 1989). This is

an area of particular impairment in many SLI children (Bishop, 1979; Precious &

Conti-Ramsden, 1988; van der Lely & Dewart, 1986; van der Lely & Harris,

1990). If SLI children have to rely on conservative learning (i.e., direct learning

from positive evidence; Pinker, 1984) or forward linking for learning the syntactic

properties of verbs, conflict may occur between the semantic representation of the

verb, the linking rules, and the various syntactic frames the verb has occurred in.

Thus, for the SLI child hearing a verb in a set of syntactic frames, without the use

of reverse linking, multiple lexical entries may be formed, or at the very least,

conflicting information may be acquired. Therefore, the increased experience of a

verb in varying syntactic frames may only serve to confuse him rather than serving

to refine the semantic representation of that verb. This may explain why the SLI

children succeeded on the forward linking task and the comprehension of these

newly learned verbs, and yet, have previously shown an impaired performance in

the comprehension of usually early acquired verbs.

The implications for the linguistic performance of SLI children extend beyond

verb-argument structure. It could be predicted that other modules, such as

morphology, will be differentially impaired. For example, where semantic


bootstrapping (which relies on forward linking) is sufficient for acquisition of morphological forms, SLI children should not show a significant impairment. Clahsen’s (1989) data from German SLI children show exactly this pattern. For example, inherent features of articles such as definiteness and indefiniteness, which can be acquired through semantic bootstrapping (Pinker, 1984), are appropriate for the language abilities of the SLI children investigated by Clahsen. The data indicate that the SLI children have the DET (determiner) functional category. However, other features of the determiner phase, which do not have inherent semantic content, such as case features and gender, appear to be absent in SLI children. In German gender, which is not a primary feature of articles but assigned locally by the noun, may not be acquired through semantic bootstrapping. Clahsen (1989) found that gender marking on articles was specifically impaired in SLI children. He characterized the expressive language of his German SLI children as being consistent with a deficit in grammatical agreement within phrase structure. The findings from this study at one level concur with Clahsen’s claim but they suggest that this characterization is too narrow and that the SLI children’s deficit also extends to the asymmetrical syntactic relationships between constituents.

To conclude, a deficit with the syntactic structural relationships can account for both the morphological characterization of SLI children and the semantic- syntactic mapping abilities shown in this and previous studies. Further research is needed to substantiate and refine the proposed linguistic characterization of this subgroup of SLI children and to establish the scope of the proposed deficit; for example, whether the deficit is “domain specific” to just grammatical representations, restricted to specific modules within grammar, or whether it is a more general language deficit for dependent structural relationships between representations. Binding theory is currently being tested as a first test of the predictions.

Conclusion

This study has shown that SLI children are able to use forward canonical linking productively to learn the syntactic properties - verb argument structures - for novel verbs. In contrast to this finding, the SLI children appear to be significantly worse in their ability to use reverse canonical linking productively to assign thematic roles to syntactic functions of a novel verb. Differences in the syntactic representations required for forward versus reverse linking can account for the findings. I proposed that reverse linking requires a more detailed representation of the syntactic structure than forward linking owing to the many-to-few mapping between thematic roles and syntactic functions. I have argued that a syntactic representation which specifies each particular syntactic


frame and all the argument positions within that frame is required for reverse

linking (in other words, the overall structural relationship between the verb and

its arguments). The SLI children appear unable to analyse the syntactic argument

positions within a particular syntactic frame. A linguistic characterization of this

deficit is constrained by previous investigations of SLI in children, as any

hypothesis must also account for these data. I proposed that a deficit in the area

of government or locality which underlies c-selection and specifies the syntactic

relationship between constituents can account for the data from this study and

data from previous investigations of SLI children. The hypothesized deficit of

government in SLI children makes clear predictions, but these involve a very

broad range of syntactic processes. Further research is required to explore the

claims, both in relation to the differences in the syntactic representation required

for using linking rules in a forward versus reverse direction, and in relation to the

underlying deficit in SLI children. Testing the predictions raised by this study may

not only help to identify more precisely the underlying cause of SLI but may also

help to identify modular components in universal grammar.

Finally, the study of SLI children can provide insight into language acquisition

mechanisms which could not be provided from investigations into normally

developing children.

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Appendix A: Raw scores for the language tests for the SLI children and LA

controls

Chronological Mean Language tests

age (months) language

RDLS BPVS ITPA BAS -

age

SLI children MP 114 77

oc 78 70

SJ 84 70

AS 80 67

AW 73 56

DL 88 43

Mean

SD

LA controls MPl 77 75 49 18 17

MP2 76 75 57 19 16

MP3 66 78 68 26 16

OCl 66 70 55 22 14

oc2 65 70 54 20 15

OC3/SJl 76 67 53 16 17

SJ2 71 69 53 14 16

SJ3 66 73 56 18 16

AS1 62 64 43 13 16

AS2 67 67 51 19 15

AS3 66 63 50 17 14

Awl 56 56 36 16 15

AW2 56 52 36 11 13

AW3 63 59 41 13 15

DLl 40 37.5 25 6 9

DL2 40 47.5 25 11 13

DL3 41 43.5 28 8 10

Mean 45.88 15.71 14.52

SD 12.34 5.08 2.24

62 68

64 49

64 51

63 49

62 41

46 23

60.17 46.83

6.98 14.68

22 15

15 16

10 16

21 13

13 13

8 11

14.83

5.71

14

2.0

Note: RDLS = Reynell Developmental Language Scales. BPVS = British Picture

Vocabulary Scale. ITPA = Grammatical Closure subtest from the Illinois Test of

Psycholinguistic Abilities. BAS = Expressive vocabulary from the British Ability

Scale.


Appendix B: Test sentences used in Experiment 3

Active 1. The man yols the lady.

2. The girl wooks the boy.

3. The boy voozes the girl.

4. The lady faps the man.

5. The car lats the lorry.

6. The car neeks the train.

7. The lorry gams the car.

8. The car sarts the lorry.

Passive

9. The man is yolled by the lady.

10. The girl is wooked by the boy.

11. The boy is voozed by the girl.

12. The lady is fapped by the man.

13. The car is latted by the lorry.

14. The car is neeked by the train.

15. The lorry is gammed by the car.

16. The car is sarted by the lorry.

Locative

17. The man jids the girl to the lady.

18. The girl mips the boy to the man.

19. The lady pons the man to the girl.

20. The boy wids the girl to the man.

21. The train shogs the car to the lorry.

22. The car rits the train to the lorry.

23. The lorry tugs the car to the train.

24. The train foons the lorry to the car.

Appendix C: Experiment 1: Forward linking. Examples of the responses for

three SLI children and three LA control children

Verb: Tiving

Demonstration by experimenter: The girl bounced the boy on his head whilst

holding him upside down.

Question 1. Tell melthe puppet what’s happening

Child Response

MP Tiving

AW They’re both tiving


DL She’s tiving

OCl The girl’s tivined the boy

SJl This is . . . it’s tiving

AS1 The boy’s been tived by the girl.

Question 2. Tell melthe puppet about the girl (agent)

Child Response MP The little girl is tiving . . . the boy

AW The girl is carrying the boy

DL Tiving him

OCl The girl’s holding the boy

SJl She’s tiving the boy

AS1 The girl’s been tiving the boy

Question 3. Tell melthe puppet about the boy (theme)

Child Response MP The boy is tiving the girl

AW The boy’s got tiving by the girl

DL The boys’ hurting his head

OCl The girl’s lifting up the boy . . . upside down

SJl The boy’s being tived by the girl

AS1 The boy’s been tived by the girl

Appendix D: Experiment 3: Reverse linking. Examples of the acting out

responses to one transitive active test sentence by three SLI children and three

LA control children

Test sentence: The man yols the lady

Child MP

AW

DL

OCl

SJl

AS1

Response The man and lady were picked up. The lady was made to push

the man over.

The lady was picked up and made to hit the man.

The man was picked up, followed by the lady. The man was

made to stand beside the lady. The lady fell over.

The man is made to turn the lady over, and then he jumps up

and down on her back.

The man is made to carry the lady.

The man and lady are picked up. The lady’s feet are attached

around the man’s neck. The man is made to walk around the

table carrying the woman.

canonical linking rules: forward versus reverse linking in ......canonical linking rules for mapping...

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