Dept. for Speech, Music and Hearing

Quarterly Progress andStatus Report

The nature of distinctivefeatures

Fant, G.

journal: STL-QPSRvolume: 7number: 4year: 1966pages: 001-014

http://www.speech.kth.se/qpsr

I. THEORY O F DISTINCTIVE FEATURES

A. THE NATURE O F DISTINCTIVE FEATURES * G. Fant

Introduction

The following es say i s intended a s a review of my own thinking on

distinctive features. Of al l that has been wri t ten on this topic I have

followed up only a par t . I a m m o r e practically oriented than linguists

and l e s s bound to orthodox acceptance of working principles but I find

i t fascinating to s i t down and work out alternative solutions, e. g. , to

o r d e r the Swedish vowels which was one of my ear ly in te res ts .

A substantial revision of our old "Prel iminaries" has long been

overdue. The major principles a r e s t i l l valid but I feel we need much

more factual data before a substantial revision can be undertaken.

Ti l l then the following mater ia l may se rve a s an expression of my

views on the subject.

Specialists i n language and speech have displayed ra ther diverging

reactions to the theory of distinctive features and misunderstandings

have been frequent. Does i t provide a condensed presentation of the

most useful facts about speech o r is i t just an intellectual game, a

purpose of i tself for the s t ruc tura l linguist? High init ial expectations

of finding new and simple solutions to central problems of speech

analysis, such a s automatic speech recognition, have been followed by

dis t rust . Now, the theory of distinctive features is not intended as a

working recipe for technical application but i t can provide some organ-

izational principles and suggestions. The ra ther specific terminology 19 of the " ~ r e l i m i n a r i e s ' ( ddea not stand for e i ther radically new o r very -

special features . The articulatory, acoustic, o r perceptive cor re la tes

of distinctive features should comprise condensed t ransforms of the

most relevant information f r o m any of these s tages within the complete

* This i s a preprint version of a paper to be published by Mouton & Co. i n Festschrif t for Roman Jakobson on the occasion of his 70th birthday, October 11, 1966.

speech communication systems. A continued study of alternative solu-

tions and descriptive forms i s needed i n the development of the dis-

tinctive feature theory a s i n speech analysis in general.

What is then really the concept of distinctive features? How a r e

they defined, from the speech wave, f rom articulation, o r from per-

ception? Are they simply a part of the linguistic code for decomposi-

tion of phonemes in a bundle of smaller units? Reading the ' 'Prel im-

inaries" one finds that the distinctive features operate on al l four

levels but f rom which one do you s tar t the analysis? Here as in

phonemic analysis the set of distinctive features constitutes abstract

units of the message code. The distinctive feature i s a choice between

one of two alternatives. In llPreliminaries" distinctive features a r e

referred to by t e rms as "discriminations", "choice", and llselectionl'

stressing the linguistic level. A distinctive feature generally recurs

a s a choice situation in several minimal distinction pairs within a

language ancl i t i s of course required that the physical o r physiological

manifestations be consistent, i. e . , one and the same feature shall have

qualitatively the same articulatory, acoustic, and perceptive correlates

independent of context of other features within the bundle. The modifica-

tion "qualitatively" here implies that the relation between the two op-

posites i s the same i n all contexts. Absolute values of descriptive

parameters , however, generally vary with context. Failure to re-

cognize the role of contextual bias i s a frequent source of misunder-

standing of the nature of distinctive features. A distinctive feature is

by definition the same in all contexts. The associated physical phe-

nomena, on the other hand, referred to a s "correlates", "cues1t, o r

"parameters" need exhibit only relational invariance.

Distinctive features a r e really distinctive categories o r classes

within a linguistic system but just like in accepted phonemic analysis

it i s required that they a r e consistent with the phonetic facts and these

phonetic facts on various levels have lent their name to the features.

It i s not within my competence to discuss the generality of distinctive

features but i t i s apparent that they comprise, as they should, the

essentials of the framework of classical phonetics and in addition some

categorizations of a more novel appearance.

I shall now proceed to some specific points concerning distinctive

features some of which a r e often brought up in discussions.

How important i s the binary principle?

The binary principle obviously has i t s basis in the presence versus

absence of an articulatory o r phonatory event, e. g . , presence versus

absence of voicing, nasality, occlusion, etc. o r in a selection of one

of two polar alternatives along a continuous parameter scale, e. g . , more open as opposed to less open. In the analysis of vowels i t can

be motivated to recognize more than two significant levels of one and

the same parameter, cif., the discussion on compactness in "prelim-

inaries", paragraph 2.414. As indicated in the analysis of the Swedish

vowel system later in this paper one could conceive of instances, where

up to 4 distinct levels of one and the same feature might be considered.

In these instances a decompoqition in t e rms of two binary categories

i s generally undertaken in order to allow a consistent use of the binary

principle within the whole system.

The distinctive feature represents the linguist' s condensed view of

the minimal units for composing speech messages. If properly applied,

categorization according to binary principles need not come in conflict

with the physical reality. It i s a matter of coding convehience only.

Economy, but at what price?

If alternative solutions of distinctive features a r e possible i t i s

sstablished policy to adopt the one providing the best economy in terms

of the smallest number of features o r rather the least redundancy

minimizing the number of alternatives that can be generated by the

specific set of categories. However, this requirement can come in

conflict with the principle of consistency, i. e . , there i s the r isk that

one o r more minimal pairs in which a feature i s supposed to operate

do not conform sufficiently well with the rest of the system. Seemingly

elegant solutions may thus have to be rejected by failures to apply in

specific contexts. It i s also apparent that the economy gained in treat-

ing consonants and vowels with the same features at times leads to

somewhat remote analogies.

Are distinctive features always orthogonal?

Distinctive features a r e handled as independent units on thc linguis-

tic level but their phonetic manifestations often lack orthogonality. The

phonetic quality of a vowel ma;r to a f irst approximation be specified

by F1 and F2. In the F F plane, however, gravity, compactness, 1' 2

flatness, and tenseness al l occupy specific vectors and interdependency

i s thus unavoidable. Even when such pa ramete r s a s F3, Fo, overall

intensity and duration a r e added i n o r d e r to provide a bet ter approxima-

tion i t i s not phonetically real is t ic to choose a consistently orthogonal

set of features.

How a r e distirictive features distributed in t ime?

People who lack training in experimental phonetics a r e generally

ra ther surpr i sed when they l ea rn that the acoustic speech wave does

not stand up very well to the ideal concept imposed by our intuitive

phonemic view of speech a s a sequence of d iscre te units with distinct

boundaries. One major shortcoming of "Prel iminaries" is the lack of

a real is t ic discussion of the t ime-varying aspects of speech patterns

and the temporal distribution of the acoustic, articulatory, and perceptual

charac ter i s t ics underlying the distinctive features which might have

s a v e d phonetically inexperienced people f rom developing an oversim-

plified, often naive, view of the segment s t ruc ture of speech.

It i s said in paragraph 2.14 of "Prel iminaries" that "For pract ical

purposes each phoneme can be represented by a quasi-stationary spec-

t r u m i n which the t r ans fe r function i s invariable with respect to t ime, , I

except i n the manner stated fo r t ransient effects". Phoneme boundaries

a r e said to be related to rapid changes ei ther in the source function o r

i n the vocal t r ans fe r function. It is also said that inherent features i n

contrast to prosodic features a r e definable without a reference to the

sequence. These rules a r e oversimplified and need to be reformulated

and expanded.

The speech spec t rogram displays a mixture of continuous and dis-

continuous elements. A successivity of "segments" i s to be seen but

what f rom the spectrograms appears to be a natural unit may constitute

only a fraction of a phoneme, e. g. , the aspiration segment o r the oc-

clusion segment of a noninitial unvoiced stop. In other instances a

piece of speech that stands out f rom the r e s t of the sequence a s a sepa-

rate unit, e. g . , i n virtue of a continuity of voicing, may be associated

with seve ra l successive phonemes.

No unique and simple rule exists fo r segmentation of speech on the

basis of nonphonemic cr i te r ia . I would claim, however, that a non-

phonemic scgmentation (1)(2) could be of value a s a rationale for a r t ic -

ulatory o r spectrographic systematizations p e r s e and a s an introductory

form of transcription before imposing the linguistic message concepts

on the signal data. The outcome of such confrontations of preconceived

linguistic structure with the observed acoustic-phonetic structure i s

that the number of physical sound segments comes out to be larger than

the number of phonemes. Because of coarticulation effects one sound

segment generally carr ies information on two o r more successive

phonemes. Conversely, a single phoneme exerts an influence on sev-

e ra l successive sound segments of the signal structure.

When i t comes to discussing the distribution of distinctive features

in time one must make clear if it i s the abstract message structure o r

the physical manifestation of speech signals that i s intended. In the

former case distinctive features a r e bounded a s the phonemes although

there can be continuity of a feature f rom one phoneme to the next. It

i s thus said in paragraph 1.1 of "Preliminaries" that "The difference

between the distinctive features of continuous bundles permits the

division of a sequence into phonemes. This difference may be either

complete, as between the last two phonemes /i/ and /r~/ in the word

wing (which have no distinctive features in common) o r partial a s be-

tween the last two phonemes of the word apt".

This statement i s correct on the message level. Indeed, the

phoneme /i/ i s categorized as nonconsonantal, vocalic, nong rave,

acute, and noncompact whereas th6 phoneme /Q/ is labelled consonantal,

nonvocalic, nasal, compact. One would accordingly expect a maximum

of acoustic contrast between the /i/ and the / r ~ / of wing.

In a multidimensional articulatory o r acoustic space, however, the

zontrast between the two corresponding segments i s minimal only. The

place of tongue articulation i s identical o r almost identical in American

English, and both segments a r e produced with a lowered velum, the

anticipatory nasalization being a normal feature generally affecting the

entire segment assigned to the /i/. The raising of the tongue against

the palate closing off the mouth cavity does not affect the sound much

since a substantial part i s directed through the nose already in the /i/

segment. In the case of a more reduced articulation the tongue never

reaches the stages of full contact with the palate and the phoneme / r ~ /

i s signalled merely a s the nasalization of the sound segment. The per-

ceptual importance of nasalization of a vowel as a cue for identification ( 3 of an adjacent nasal phoneme i s considerable .

The theory of segmentation of speech on various levels i s a well

worth object for further research and descriptive studies. The essen-

tial point to consider i s that we can measure the duration of physical

events such a s sound segments in a spectrogram but there exists no

unique method o r convention of measuring the duration of a phoneme o r

of a distinctive feature.

Specific features. Vocalic and consonantal

One of the weaker parts of the distinctive feature theory i s that of

defining consonants and vowels. It i s in my opinion quite motivated to

categorize liquids a s being both vocalic and consonantal but the classi-

fication of the consonant h (and glides) a s being nonvocalic and non-

consonantal i s a more arbi t rary construction although arguments can be

raised in favor of such a classification. The physical c r i te r ia for the

vocalic and consonantal features have not been very rigid. A small

damping of vowel formants has been one of the requirements in all

versions of the system. The f i rs t edition of "Preliminaries" s t ressed

the voiced source of vocalic sounds but the Addenda and Corrigenda

chapters of the la ter edition turned the emphasis on the formant pattern

and formulated the consonantal feature a s almost the negative of the

vocalic feature in t e r m s of formant reduction.

In "Fundamentals of Language" Jakobson and Halle (4) limit the

consonantal feature to a low intensity alone. In a study of the classifica-

tion of Swedish phonemes ( 5 ) I introduced a new formulation retaining

the concept of formant reduction in defining the consonant feature but

with intensity associated with the vocalic feature. One gain of this

formulation i s that the phoneme /h/ accordingly contrasts with vowels

a s being l ess intense. Also /h/ differs f rom other consonants i n the

lack of pattern contrast with adjacent vowels, motivating the minus

consonantal feature.

The study of Fant (1960)~ see ief . ( 5 ) y also includes comments on

the theory of the syllable. The syllable nucleus must possess the voc-

alic feature and i t displays a temporal contrast with respect to adjacent

sounds i n t e rms of either higher intensity o r a more vowellike structure.

Syllabicity should not be ascribed to intensity alone.

~ e n s e / l a x and voiced/voiceles s

The subject of tense and lax vowels and consonants has been given

a thorough treatment by Jikobson and Halle (6). Their view on the

subject does not depart substantially from that expressed in our ear l ier

joint work. The tense versus lax opposition i s intended to operate in

vowels as well as in consonants. Tenseness i s phonetically described

by an articulation with grea ter overpressure behind the place of the

active source; in the case of vowels a higher subglottal pressure and

in the case of stops and constrictives a higher pressure behind the

place of articulation. Furthermore tenseness i s associated with a more

extreme articulation and with a grea ter t ime spent in an extreme art i - ,,.- .

culatory position.

The two last mentioned characteristics were mentioned in our ear,

l ie r work but I a m somewhat sceptic about the higher overpressure,

This factor when present indeed adds emphasis to tense consonants

but in my opinion i t has not been sufficiently well documented in exper-

imental work. Recent studies of Mal6c 6' t suggest that the combined ef-

fect of pressure and duration expressed a s a pulse integral could have

a role i n proprioceptive feedback. In my experience Swedish voiced

and unvoiced stops a r e produced with the same subarticulatory pressure

at the instance before release. This does not prove anything for Eng-

lish but i t seems probable that the pressure factor, i f present, a s a

constituent in the opposition between American English unvoiced and

voiced stops, i s of relatively small significance and a secondary effect

of glottal articulation. Several recent studies support the view of Lisker

and Abramson ( 8 ) that i t i s the glottal articulation that i s the basic

factor.

The longer duration and higher intensity of the noise interval follow- . .

ing at the release of an unvoiced stop compared with voiced stops a r e

physiologically due to a later closing of the vocal cords af ter the re-

lease. The pulmonary pressure appears to be the same. Studies of

subglottal pressure i n Swedish speech do not reveal any difference in

the pulmonary activity comparing voiced and unvoiced consonants o r

short o r long vowels. I really doubt that subglottal pressure would

have anything to do with the tense-lax opposition among English and

French vowels.

On these grounds I hesitate to accept the use of the tense-lax oppo-

sition among American English consonants as well as vowels suggested

by Halle (9). It should be used in the vowel system but withbut ref-

erence to subglottal pressure. Within the consonants it would be just

as motivated to use the voiced-voiceless distinction as the tense-lax

distinction. The economy gained by one and the same feature operat-

ing in vowels as well as in consonants i s of course desirable but e-- I find

it -- more - important .. -.. to - . retain . - . a close correspondence . . ... . between phonetic

facts and fcature criteria. We need more experimental data to illu- 7 ,- "-. .

minate this very interesting problem.

Distinctive features and perception

I do not hold the view that the decoding of speech in the brain up to

the level of phonemic identification has to follow a functional scheme

strictly conforming with a distinctive feature system of language anal-

ysis. This does not imply that I consider distinctive features unimpor-

tant in speech perception. Distinctive features as phonetic classes a r e

a psychological reality as judged from confusion tests under varying

types of distortion o r mental disturbance. Even in rapid mimicking ( 10)

the decoding proceeds along phonetic classes so that, e. g. , place of

articulation may be confused whilst the category of stop sound is cor-

rectly recognized.

When constructing models of speech perception we should not limit

our choice to a representation in t e rms of either allophones o r features.

On the contrary it seems reasonable that a decoding in terms of phon-

etic classes (distinctive features) i s paralleled by a direct attempt of

all ophone decoding. I am thus more in favor of a parallel analysis of

features than of a ser ia l analysis with a succession of decisions.

The question whether a translation to equivalent motor instructions

precedes phonemic identification i s not important. Of greater impor-

tance i s to study what aspects of known features a r e of primary impor-

tance to perception (I1) . It i s observed that in some instances it i s the

temporal contrast of two successive sound segments (e.g., stops,

laterals, nasals) rather than the inherent quality of each of the segments

that evokes the particular auditory sensation associated with the partic-

ular class (feature). The pertinent problem i s to find what transforms

we should apply to the speech wave data in order to extract the informa-

tion bearing elements that operate in speech perception. Attempts to

avoid the search for auditorily relevant sound characteristics by an

uncritical acceptance of the view that perception is merely a recon-

struction of the production does not appear very fruitful.

Given a distinction, let us say between the phonemes /k/ and /t/ o r

between the phonemes /g/ and /d/, the procedure would f i rs t of all be

to study a number of minimally contrasting pairs i n different vowel

contexts.. As a precaution for securing that we have not lost any sig-

nificant information i n the acoustic specification of a feature, i t i s ad-

visable to consider the underlying production events and apply known

transformation rules. Second formant loci a r e known to be effective

cues for discriminating place of articulation but they a r e not sufficient.

Indeed, a vowel context can be found such that the F2 transition is

almost the same for /k/ and /t/ o r fo r /g/ and /d/. This is the vowel

1 . This ambiguity in F2, observed by Liberman 1957 ('')(see Fig.

3 in his paper) led him to conclude that "articulation goes one way and

the speech wave another way" and since we can discriminate lga/ from

/ da / perception follows articulation, not the speech wave. The am-

biguity is resolved i f we add the information of the third formant and

the burst portion.

In a recent experiment (see Section 111. A) by Fant, Lindblom and

de s e r p a - ~ e i t g o we low-pass filtered Swedish and English stops at

2000 c/s. The result was that our bilingual speaker, now serving

a s a listening subject, classified all his filtered Swedish /t/ a s /k/ and

his /d/ and /g/ and likewise almost al l his British English /t/ a s /k/.

Since the filtering removed the upper part of the burst spectrum of the

dentals there remained very little difference between the unfiltered

/k/ and the filtered /t/.

This experiment supports the view that the effective acoustic feature

i s the combination of the second and the third formant and the burst

concentrating the energy in the palatals and velars in a frequency region

at o r above the effective upper formant of the vowel, see Fant (13)

pp. 217-218. My formulation above of the perceptually relevant char-

acteristics of compactness i s not claimed to represent the final answer.

Also I do not claim that a formulation found effective for contrasting

/k/ and /t/ must be exactly the same a s that contrasting /n/ and /n/.

The human brain surely has a sufficiently large capacity to identify / r ~ /

a s different f rom /n/ in a space separate f rom that discriminating /k/

and /t/. It seems quite likely that feature analysis i s an important

aspect of speech recognition, adding to the economy of the system.

On the other hand, i t seems likely that perception works according to

more redundant principles than those guiding linguistic analysis. Here

I believe Roman Jakobson agrees with me that speech perception i s

not merely the neural decoding of his twelve-features.

Recent studies of Chistovich et a1 i n Stockholm have revealed in-

teresting results concerning vowel perception. These studies (14)

support the view of a categorical perception of isolated vowels and the

existence of an FIFZ quantization i n accordance with our working prin-

ciples of acoustic phonetic analysis.

Swedish vowels

The Swedish vowel system i s generally presented in t e rms of 9 long and 9 short phonemes. Special p re - r variants of the open un-

rounded and rounded front vowels in Swedish orthography a and o stand

out a s well recognized allophones of an especially "open" quality.

The following phonemic symbols referred to as the STA alphabet

will be used for the 9 vowels. Approximate IPA symbols a r e included

a s examples of phonetic values in contexts other than before [ r] . Index 1 stands for long vowel, 2 for short vowel, and no index implies

either long o r short, i. e, length distinction omitted.

Group STA IPA STA IPA

I Back vowels O 1 u: O2

I1 Unrounded i i: i 1 2 I front vowels e 1 e: ez e - E

a l E: Z2 E

I11 Y1 Y: Y2 Y front vowels

' 1 u: ' 2 0

In my f i rs t attempt of ordering ( I5 ) I chose to oppose group I to

group I1 and I11 in t e rms of the grave/acute distinction and group I11

was naturally opposed to group I1 in t e rms of the f l a t /~ l a in featurc.

So fa r my views have not changed. However, a division within the

three major groups in t e rms of articulatory opening, i. e. , the com-

pactness feature classifying not only /bl / and /el / but also by an

intermediate + - degree of compactness did not conform well with phonetic

facts, the F1 of /u1/ being the same as the Fl of /Y1/. Also within

the short vowels the FI of /uh/ was generally not significantly different

from the F1 of /e2/. I therefore chose in later works (5)(16)(17) to

use three degrees of flatness assigning an intermediate value of flatness

to the phonemes /y/ and /ti/ and to the honeme /u/ the maximal degree Pl8) of flatness, as suggested by Malmberg . This conforms well with

the flatness cri teria of low F1 + F2 + F3 and the extreme degree of

lip-rounding in the /u1/ and /ol/ phonemes. In group I either flatness

o r compactness in three levels can be used for the further division.

An alternative solution which perhaps comes closer to the vicws of

Roman Jakobson would be the following. In group I flatness i s used to

separate phonemes /o/ (IPA -. u) and /3/ (IPA o) from /a/, and /&/ is

opposed to /o/ by the greater compactness. Now in group I1 and 111

the opposition ~ h a r ~ / ~ l a i n i s introduced to differentiate /i/ and /e/

from /1/ and /y/ and /6/ from /u/. * The criterion of sharpness i s

higher F2 and F j everything else being equal. In this sense sharpness

i s given a function similar to that of diffuseness in Halle' s vowel

analyses (9). By this arrangement one avoids introducing three degrees

of flatness o r compactness and four binary features specify the entire

system, as shown on next page.

Feature 1 o 3 a 1 i e 1 y u o

* Suggested by S. ohman, personal communication.

I I - - -

+ + + - - - +

1 grave + + + 1 - - -

I ! I I

flat + t - - - t

compact - - t i f +

In this solution /u/ differs f rom /a/ by two features . Within the

sys tem of shor t vowels /ti2/ i s opposed to /uZ/ pr imar i ly by the sharp-

ening whereas within the long vowels /al / differs f rom

/u / primari ly in t e r m s of g rea te r compactness. 1

A smal l variation of the sys tem allowing a c loser relational cor -

respondence of /e/ to /u/ is the following:

-- -

y u a ! - - -

t t t

- - t

i e a

- - -

- - -

Feature o P a 1

grave t + t I I

Concluding r emarks

The concept of distinctive features requires an integrated view of

speech patterns at each stage of the speech communication chain and

should not be confused with the concept of cue which is l imited to a

detail of the pattern. Several cues make up a feature. The p r imary

a i m of the phonologically oriented analysis such a s the one underlying

my work together with Jakobson and Halle was to make an integrated

formulation of those cues which a r e i n common i n al l contexts where

the feature operates . There is a potential danger that this demand f o r

generali ty dilutes the discr iminatory power of the formulation i n any

specific context. In spite of frequent reference to contextual bias in our

work misunderstandings have occurred, especially among those entering

the field of phonetics.

flat t t -

compact

sha rp

Y u a

t t - 0 0 0

i e 2 Fea tu re

t t

t - t

o a

I

jgrave I t + + i - - -

- f +

- - - I

flat I t t - i t t t I

compact

sha rp

- 1 - - t + I - - t 1 - - t

i I I

0 0 0 i + - - t 1

The generalized formulations of our features pr imar i ly se rve a

function in summary views of a phonological system. If we a r e in-

terest&n speech communication mechanisms we must take into con-

sideration all perceptually important information i n each specific

context where the feature operates. Contextual b i a s represents " re-

dundant features" f rom a res t r ic ted s t ruc tura l point of view.

In my view this terminology is conceptually misleading when dis-

cussing the perception of speech. What is redundant f r o m a narrow

metalinguistic point of view may comprise essent ials of the actual code.

This amounts to saying that the major allophones of a language would

have a perceptual reali ty a s individuals whereas we need not anticipate

that the bra in possesses a catalogue of all possible contextual var ia-

tions of a feature o r of a phoneme. The concept of the distinctive

feature appears to be a reali ty in perception.

Most of the manner of production features a r e c l ea r cut and the

same i n a l l contexts. It is outside my competence to discuss the univer-

sali ty of features except in a very general sense. I consider the d is -

tinctive features to be a very powerful concept based on the natural

constraints of our speaking mechanism. The se t of features we have

been operating with is not unique. Alternative solutions, affecting

some of the features , a r e possible within some languages a s well a s

when dealing with s imi lar phenomena in two different languages.

The universal acceptance of the basic concept of feature analysis

i s much due to the inspiring work of Roman Jakobson.

References

( i ) Fant, G. : "Descriptive analysis of the acoustic aspects of speech1! Logos - 5 (1962), pp. 3-17.

(2) Fant , G. and Lindblom, B. : "Studies of minimal speech sound units", STL-CPSR 2/1961, pp. 1-1 1.

(3) MArtony, J.: "The role of formant amplitudes in synthesis of nasal consonants", STL-GPSR 3/1964, pp. 28 -3 1.

(4) Jakobson, R. and Halle, M. : Fundamentals of Language ( ' s-Gravenhage 1956).

(5) Fant, G. : f iStructural classification of Swedish phonemes", STL-CPSR 2/1960, pp. 10-15.

(6) Jakobson, R. and Halle, M. : "Tenseness and laxnessu, Solccted Writin I by K. Jakobson ( ' s-Gravenhage 1962)' pp. &

cant. next page

(7) Malecot, A. : "Mechanical p res su re a s an index of ' F o r c e of Articulation' It, Phonetica - 14 (1966), pp, 1 59- 180.

(8) Lisker , L. and Abramson, A. S. : "A cross-language study of voicing i n initial stops: acoustical measurements f t , Word 20 (1964), pp. 384-422.

(9) :Halle, M. : llPhonology i n generative grammar" , Word - 18 (1962), pp. 54-72.

(10) Kozhevnikov, V. A. and C histovich, L. A, : Speech: Articulation US Dept. of Commerce,

1965).

(1 1) Fant , G. : "Auditory patterns of speech", to be publ. in the P roc . of the Symp. on Models for the Percept ion of Speech and Visual F o r m , Boston, Mass. , Nov. 11- 14, 1964.

(12) Liberman, A. M. : "Some resul ts of r e sea rch in speech perception", J. Acoust. Soc. Am. - 29 (1 957), pp. 358 -368.

(13) Fant, G. : Acoustic Theory of Speech Production (' s-Gravenhage 1960).

(14) Chistovich, L. et a l . : ''Mimicking of synthetic vowelstf, STL-GPSR 2/1966, pp. 1-18;' and Chistovich et a1. : "Mimicking and perception of synthetic vowels, P a r t II", STL-GPSR 3/1966, pp. 1-3.

(15) Fant , G.: "Phonetic and phonemic bas is for the transcription of Swedish word material", Xcta Oto-Lar . , Suppl. 116, (1954), pp. 24-29.

(16) Fant, G. : "Acoustic analysis and synthesis of speech with applica- tions to Swedish", Er icsson Technics - 15 (1959), pp. 1-106.

(17) Fant, G. : "Modern instruments and methods for acoustic studies of speech" , Acta Polytechnics Scandinavica 246/1958, 84 p.

(18) Malmberg, B.: "Distinctive features of Swedish vowels. Some instrumental and s t ruc tura l datau, F o r Roman Jakobson (' s-Gravenhage 1956), pp. 3 16-321.

(1 9) Jakobson, R. , Fant , G. , and Halle, M. : "Pre l iminar ies to speech analysis. The distinctive features and the i r co r re l a t e s i t , Acoustics Laboratory, Massachusetts Institute of Technology, Technical Report No. 1 3 (1 952), 58 pp. ; 4th printing publ. by The M. I. T. P r e s s , Cambridge, Mass. 1963.

(20) Fant , G., Lindblom, B. , and de s e r p a - ~ e i t c o , A.: "Consonant confusions in English and Swedish - a pilot study", section 111. A in this i ssue of STL-C-PSR,