guidelines for promoting intelligibility john m. levis iowa state university [email protected]
TRANSCRIPT
Why I am exploring this topic?
Intelligibility is widely agreed to be the most important goal for spoken language development, for both listening and speaking
It is the most important goal for ESL settings and for non-ESL settings (both where NNSs will interact with NSs and where they interact primarily with other NNSs)
Intelligibility is a moving target, depending on the interlocutors, situation, register, and other elements of context. Thus, context-sensitive principles are needed to make decisions.
Overview of talk
What is intelligibility?Why is it important?What is thought to promote intelligibility?The segmentals/suprasegmentals
debateGuidelines for promoting intelligibilityNuanced intelligibility –
Recommendations
What is intelligibility?
General definition “Intelligibility may be broadly defined as the
extent to which a speaker’s message is actually understood by a listener” (Munro & Derwing 1999, p. 289)
This broad definition implies at least two different types of understanding
Successfully identifying wordsUnderstanding a speaker’s intended meaning
Successfully identifying words
Intelligibility (technical definition) The ability of listeners to accurately decode
individual words in the stream of speech or, The ability of a speaker to say words in such a
way that listeners can decode them
Pronunciation deviations do not necessarily impair the ability to decode, e.g. Dialect pronunciations English as a Lingua Franca (Nonnative) speaker
pronunciations
Understanding intended meanings
Comprehensibility (two definitions) The accuracy with which a speaker’s intended
meaning is perceived (this implies a way to measure comprehension)
Hahn (2004)
The perception of how easy it is to understand a speaker (this implies a more global view of comprehension that trusts listeners’ intuitions)
Derwing and Munro; Munro & Derwing (various references)
Why is this important?
Teaching for intelligibility/comprehensibility implies a principle of differential importance Some pronunciation errors are more likely to affect
understanding than others Some pronunciation teaching topics should be
emphasized while others should not There’s a practical reason as well. It is rare to
have courses devoted to pronunciation instruction. So we need to make changes quickly and effectively. “Triage” (Judy Gilbert)
Native-like accents and intelligibility
Intelligibility assumes that native-like pronunciation is not an important goal; Rather, it’s important to be understandable even if accented. Why not a native accent? It doesn’t seem to be possible for most learners It’s not necessary (unless you’re a spy) Language proficiency does not depend upon having
a native-like accent Everyone, even native speakers, has an accent.
“Being native-like” usually means privileging one accent above other appropriate accents.
What promotes intelligibility?Some proposals
A focus on suprasegmentals “…a short-term pronunciation course should
focus first and foremost on suprasegmentals, as they have the greatest impact on the comprehensibility of learners’ English” (McNerny & Mendelsohn, 1992, 186)
An emphasis on the big picture “The Zoom Principle” “A pronunciation syllabus should begin with
the widest possible focus [i.e., general speaking habits] and move gradually in on specific problems” (Firth 1992, 173)
Attending to errors that affect NNS understanding Most speakers of English in the world are NNSs
who speak English with other NNSs. Multiple Englishes imply a need for an
internationally understandable norm “if we are to provide appropriate pedagogic
proposals for EIL pronunciation, then these must be linked directly to relevant descriptions of NNS speech…in terms of what constitutes optimum productive competence and what learners need to be able to comprehend” (Jenkins, 2002, 84)
Segmentals vs. Suprasegmentals
The traditional debateSuprasegmentals are more likely to promote
comprehensibilityBut, segmentals are obviously importantBut, suprasegmentals are more likely to
reveal common problems across a range of first language backgrounds
But….
Why the debate is not useful You can’t have one without the other Rhythmic structure (a suprasegmental) and vowel
quality (a segmental) are interdependent, e.g. récord vs. recórd
Rhythmic structure and consonant clarity are closely connected (e.g., aspiration of initial stops – rappél vs. rápid; deletion of /h/ in unstressed syllables – Did he do it? are affected by stress patterns
Differential importance applies within categories as well as across categoriesFinal consonant errors in Vietnamese-
accented English impair listener understanding more than initial consonant errors (Zielinski, 2006)
Field (2005) studied listeners’ ability to understand 2-syllable word stress errors with and without changes in vowel quality. He found that there is “ a significant decrement in intelligibility when stress is shifted to an unstressed syllable without an accompanying change in vowel quality” (p. 414). “When the stress shift was accompanied by a change in vowel quality (from weak to full) the loss of intelligibility was considerably less marked” (p. 415)
Seven Guidelines for teaching for intelligibility
Derwing & Munro (2005) call for decisions about pronunciation teaching to be based on research. This is important, but as they admit, there is not enough research yet to base all decisions on it. So,Some of my guidelines come from researchSome come from practice
These are offered in no particular order of importance and show some overlap
Seven guidelines
Functional loadFrequencyPotential for penaltyProbability of offenseLexical importanceProcessing constraintsLearnability
Guideline 1: Functional load
[Functional load] “is a measure of the work two phonemes do in keeping utterances apart” (King, 1967, as cited in Munro & Derwing 2006, 522). Functional load is measured partly by# of initial minimal pairs two sounds have# of final minimal pairs two sounds haveLikelihood that the distinction is enforced in
all varieties of English
Munro & Derwing 2006
Tested NS subjects’ listening to sentences with high and low functional load errors High functional load errors
/l/-/n/ (light-night), /s/-/ʃ/(sell-shell), /d/-/z/ (ride-rise) Low functional load errors
/ð/-/d/ (then-den), /ɵ/-/f/ (three-free) Subjects rated accentedness and
comprehensibility of the sentences Accentedness (on a scale of 1-9) Perceived comprehensibility (on a scale of 1-9)
Low FL errors and accentedness “the presence of one, two, or three low FL
errors resulted in significantly worse judgments of accent than the presence of no errors” (527)
High FL errors strongly affect comprehensibility “high FL errors had a significantly greater
effects on the listeners’ ratings [for comprehensibility] than did low FL errors. Even sentences that contained only one high FL error were rated significantly worse for comprehensibility than sentences containing three low FL errors” (527)
ConclusionsErrors in phonemes that carry a high
functional load are more likely to affect listeners ability to understand than are errors with sounds that carry a low functional load
Guideline 2: Frequency
Base Belief: Speech that contains more phonetic and phonemic errors will be less understandable than speech that contains fewer
“unintelligibility…[is] the cumulative effect of many little departures from the phonetic norms of the language. A great many of these may be phonemic; many others are not. Under certain circumstances, any abnormality of speech can contribute to unintelligibility”
(Prator & Robinett, 1985, xxii)
Munro & Derwing 2006
There is some evidence for and against this concept, again from the previous study on functional load
Low FL errors and frequency “the presence of one, two, or three low FL errors
resulted in significantly worse judgments of accent than the presence of no errors. However, sentences with two or three low FL errors were not rated as more accented than sentences that contained a single FL error. In other words, there was no evidence of a cumulative effect of low FL errors on accentedness” (527)
Frequency of high FL errors and accent “Although…the presence of one or two high
FL errors led to a significant increase in the perception of accentedness over the no-error condition, sentences containing two high FL errors were rated as significantly more accented than sentences containing only one high FL error. In other words, a cumulative effect of high FL errors was seen” (527)
Frequency of high FL errors and comprehensibilitySentences with one and two high FL errors
were equally comprehensible “It may be…that numbers of segmental
errors alone do not account fully for variability in accentedness or comprehensibility. Rather, the nature of the errors may affect their performance” (530)
Guideline 3: Potential for Penalty
Certain contexts of use have higher stakes for the speaker and listener than others. If you’re selling in a shop in an area where ethnic shops are the norm, your needs for understandable pronunciation are lower than if you are a doctor or a nurse. Some high stakes areas: Education (International teaching assistants) Health (Medical personnel) Translation (Spoken language translators)
While this principle is important, it also opens the very real possibility of prejudicial judgments of speech that have nothing to do with being understoodRubin (1992)Lippi-Green (1997)Munro (2003)
Guideline 4: Probability of offense
When mispronunciations sound like taboo wordsBeach, sheet, piece (/i/ vs. /I/)Taboo sound-alikes can come up in very
unexpected placesFrench class – speaking about silverware,
students were being unresponsive, teacher changed to English “ A fork [sounded like “fuck”]! Haven’t you ever had a ‘fuck’?]
“focus”
These kinds of mistakes carry the possibility of extreme distraction or embarrassment and need to be addressed, either by instruction or avoidance
Taboo sound-alikes fit with a concept related to intelligibility/comprehensibility, irritation. Irritation can occur whenever a listener finds speech understandable but unpleasant for some reason, such as type of accent.
Guideline 5: Lexical importance
Some words carry key content more than others This is especially important in high stakes communication contexts.
Ability to guess meaning from context in reading comprehension is impaired when fewer than 95% of the words are known. When fewer than 80% of the words are known, the ability to understand is very low (Nation 1990)
If these are the figures for reading, where the permanent nature of the text is a significant help, what must they be for listening?
Example: International Teaching Assistant instruction Most ITA training has an emphasis on pronouncing
key technical vocabulary correctly There is also often attention to pronouncing key
sub-technical vocabulary (words that cut across disciplines, such as develop) understandably
When content is unfamiliar, understanding is impaired both by the subject matter and the way the content is packaged (the spoken qualities of the message)
Guideline 6: Processing constraints
Unfamiliar messages will take longer to process than will familiar messages Familiarity in content Familiarity in speech style
Heard “coROLLary” in a talk by Wilga Rivers when I expected “COroLAry” It took me 45 seconds to unpack the segmentals
NNS listener perceptions (Jenkins 2002) – “let cars” and “clay houses”)
NS perceptions (Munro and Derwing) Expected mistakes vs. unexpected ones
When knowledge of the world (top-down processing) and the understanding of the speech details (bottom-up processing) do not match, NS listeners will first try a top-down interpretation that makes sense. If that does not work, they will try to process from a bottom-up perspective. Or they will give up.
If there is insufficient knowledge of the world (top-down knowledge) then listeners must rely more heavily on bottom-up processing.
There is evidence that L2 learners rely more heavily on bottom-up processing than do L1 learners in their native language
When processing constraints interact with high-stakes listening where the potential for penalty is great, the problems can be enormous ITAs teaching in any college fieldMiranda warnings and word frequency
Reaction time research The work of Anne Cutler and her colleagues (see
Cutler, Dahan, & van Donselaar 1997 for a review) consistently shows that unexpected elements in speech affect listeners’ ability to process speech
Other research, such as John Field’s study, measure the “cases where intelligibility is entirely lost” (2005, p. 415). This kind of research is less sensitive to processing demands than reaction time research
Munro & Derwing’s research shows that loss of comprehensibility (where the speaker’s intended meaning does not seem clear) is far more common and probably more serious than loss of intelligibility (where a word cannot be understood). This is likely due to processing difficulties.
Guideline 7: Learnability
Some features of pronunciation are more learnableJenkins (2002)
[Besides not being a cause of unintelligibility in Jenkins data] “as many pronunciation teachers are aware, some of these features seem to be unteachable. That is, no matter how much classroom time is spent on them, learners do not acquire them” (97)
Some areas not included in Jenkins’ Lingua Franca core (2002) /ɵ/ (thank), /ð/ (then), /ɫ/ (will) Weak forms, especially the use of /ə/ (schwa) in
words like to, and, from. “In EIL, the full vowel sounds tend to help rather than hinder intelligibility” (98)
Final Pitch movement Levis (1999) - Pitch movement differences on certain
types of grammatical forms (yes-no questions) are not important to teach
Further evidence that some features may not be learnable
Pennington and Ellis (2000)Recognition tasks for several aspects of
intonation/stress for Cantonese speakers learning English
Contrastive sentence focus (Is HE driving the bus? Vs. Is he driving the bus?)
Final pitch movement on tags (He’s going, isn’t he? (rising vs. falling)
Phrasing (The fight is over, Fred vs. The fight is over Fred)
Internal phrase structure (She’s a lighthouse keeper vs. She’s a light housekeeper)
Recognition tasks in two conditions: When there was no previous instruction, and when there was. Subjects performed well on recognizing the words
and grammar of previously heard sentences when prosodic form was not tested
Subjects performed poorly on recognizing previously heard sentences if prosodic form was included. This was especially so when there was not previous explicit focus on form.
Training with explicit focus on prosodic form increased recognition ability only for contrastive sentence focus. The other aspects of intonation/stress were not amenable to instruction
Why did only contrastive sentence focus show improvement? “…certain aspects of prosody --- such as the
relatively universal relationship of enhanced prosody and marked meaning, as contrasted with neutral prosody and unmarked meaning --- can be more readily taught than some other more language-specific aspects [of prosody]” (p. 387)
Recommendations
Take a nuanced view of any target. It is likely that all phonological categories include more and less important features, e.g.,Consonants (Some targets are important,
some are less so – e.g., /l/-/n/ is more critical than /ɵ/-/f/ or /ð/-/d/)
Vowels (phonetic length may be more important than phonemic quality – Jenkins 2002)
Intonation (Not all kinds of intonation are likely to be equally important. Sentence focus is likely to be important (Hahn 2004; Pennington and Ellis 2000) while final intonation, especially on certain grammatical structures, is much less so (Levis 1999; Pennington and Ellis 2000)
Word Stress (e.g., Rightward misstressing affected intelligibility more than leftward (Field 2005)
Distinguish between listening and speaking Listening improvement can lead to production
improvement Learning to hear the /l/-/r/ distinction can lead to
better production for Japanese learners even without practice (Bradlow, Pisoni, Akahane-Yamada, and Tokhura1997)
Even when features are not considered learnable in normal classroom instruction, teaching the feature for reception may be critical for later acquisition outside the classroom (Jenkins 2002)
Building a range of tolerance for understanding (listener training) will develop flexibility
Recognize that not all learners need to function in the same contexts Some need to understand and be understood by
NS interlocutors Some need to understand and be understood by
NNS interlocutors “There is compelling evidence that ELF [i.e.,
NNS] interlocutors engage in communication strategies and accommodation processes that …may conflict with the ways in which NSs typically negotiate understanding” (Pickering 2006, 227)
Recognize that pronunciation is more than listening and speaking Visual support can be critical
Body language (e.g., for negation)Visual support (e.g., ITAs)
Circumlocution is useful for any speaker Oral spelling or restatement of numbers can
quickly disambiguate many situations
What might be our priorities?
Functional load and Frequency Word Stress Consonants, including high functional load
consonants, aspiration and final consonants with grammatical meaning
Vowel lengthening and vowel quality Weak forms and fast speech phenomena (for
listening) Potential for penalty, Probability of offense,
and Lexical importance Key vocabulary for speaking needs
Processing constraintsSentence FocusWord StressWeak forms and fast speech phenomena
(for listening, especially in ESL contexts)Learnability
Sentence focusGeneral speaking habits
The PowerPoint slides for this talk will be available after March 26 at
jlevis.public.iastate.edu/intelligibility.ppt
References
Bradlow, A., Pisoni, D., Akahane-Yamada, R. & Tokhura, Y. (1997). Training Japanese learners to identify /l/ and /r/: IV: Some effects of perceptual learning on speech production. Journal of the Acoustical Society of America,
Brown, A. (1989). Functional load and the teaching of pronunciation. TESOL Quarterly, 22 (4): 593-606.
Cutler, A., Dahan, D. & van Donselaar, W. (1997). Prosody in the comprehension of spoken language: A literature review. Language and Speech, 40 (2):141-201.
Derwing, T. & Munro, M. (2005). Second language accent and pronunciation teaching: A research-based approach. TESOL Quarterly, 39 (3): 379-397.
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Prator, C. & Robinett, B. 1985. Manual of American English pronunciation, 4th ed.. Rinehart Holt Winston.
Rubin, D. (1992). Nonlanguage factors affecting undergraduates’ judgments of nonnative English-speaking teaching assistants. Research in Higher Education, 33: 511-531.
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