Guidelines for promoting intelligibilityJohn M. LevisIowa State Universityjlevis@iastate.edu

Why I am exploring this topic?Intelligibility is widely agreed to be the most important goal for spoken language development, for both listening and speakingIt 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 talkWhat 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 definitionIntelligibility may be broadly defined as the extent to which a speakers message is actually understood by a listener (Munro & Derwing 1999, p. 289)This broad definition implies at least two different types of understandingSuccessfully identifying wordsUnderstanding a speakers intended meaning

Successfully identifying wordsIntelligibility (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 themPronunciation deviations do not necessarily impair the ability to decode, e.g.Dialect pronunciationsEnglish as a Lingua Franca (Nonnative) speaker pronunciations

Understanding intended meaningsComprehensibility (two definitions)The accuracy with which a speakers 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 importanceSome pronunciation errors are more likely to affect understanding than othersSome pronunciation teaching topics should be emphasized while others should notTheres 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 intelligibilityIntelligibility assumes that native-like pronunciation is not an important goal; Rather, its important to be understandable even if accented. Why not a native accent?It doesnt seem to be possible for most learners Its not necessary (unless youre a spy)Language proficiency does not depend upon having a native-like accentEveryone, 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 suprasegmentalsa 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 pictureThe Zoom PrincipleA 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 understandingMost speakers of English in the world are NNSs who speak English with other NNSs.Multiple Englishes imply a need for an internationally understandable normif we are to provide appropriate pedagogic proposals for EIL pronunciation, then these must be linked directly to relevant descriptions of NNS speechin terms of what constitutes optimum productive competence and what learners need to be able to comprehend (Jenkins, 2002, 84)

Segmentals vs. SuprasegmentalsThe 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 usefulYou cant have one without the otherRhythmic structure (a suprasegmental) and vowel quality (a segmental) are interdependent, e.g. rcord vs. recrdRhythmic structure and consonant clarity are closely connected (e.g., aspiration of initial stops rappl vs. rpid; 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 intelligibilityDerwing & 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 practiceThese are offered in no particular order of importance and show some overlap

Seven guidelinesFunctional 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 2006Tested NS subjects listening to sentences with high and low functional load errorsHigh functional load errors/l/-/n/ (light-night), /s/-//(sell-shell), /d/-/z/ (ride-rise)Low functional load errors//-/d/ (then-den), //-/f/ (three-free) Subjects rated accentedness and comprehensibility of the sentencesAccentedness (on a scale of 1-9)Perceived comprehensibility (on a scale of 1-9)

Low FL errors and accentednessthe 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 comprehensibilityhigh 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: FrequencyBase 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 2006There is some evidence for and against this concept, again from the previous study on functional loadLow FL errors and frequencythe 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 accentAlthoughthe 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 comprehensibleIt may bethat 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 PenaltyCertain contexts of use have higher stakes for the speaker and listener than others. If youre 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 offenseWhen 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]! Havent 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 avoidanceTaboo 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 importanceSome 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 instructionMost ITA training has an emphasis on pronouncing key technical vocabulary correctlyThere is also often attention to pronouncing key sub-technical vocabulary (words that cut across disciplines, such as develop) understandablyWhen 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 constraintsUnfamiliar messages will take longer to process than will familiar messagesFamiliarity in contentFamiliarity in speech styleHeard coROLLary in a talk by Wilga Rivers when I expected COroLAry It took me 45 seconds to unpack the segmentalsNNS 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 enormousITAs teaching in any college fieldMiranda warnings and word frequency

Reaction time researchThe 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 Fields 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 & Derwings research shows that loss of comprehensibility (where the speakers 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: LearnabilitySome 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)// (thank), // (then), // (will)Weak forms, especially the use of // (schwa) in words like to, and, from. In EIL, the full vowel sounds tend to help rather than hinder intelligibility (98)Final Pitch movementLevis (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 learnablePennington and Ellis (2000)Recognition tasks for several aspects of intonation/stress for Cantonese speakers learning EnglishContrastive sentence focus (Is HE driving the bus? Vs. Is he driving the bus?)Final pitch movement on tags (Hes going, isnt he? (rising vs. falling)Phrasing (The fight is over, Fred vs. The fight is over Fred)Internal phrase structure (Shes a lighthouse keeper vs. Shes 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 testedSubjects 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 instructionWhy 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)

RecommendationsTake 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 //-/f/ or //-/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 speakingListening 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 contextsSome need to understand and be understood by NS interlocutorsSome need to understand and be understood by NNS interlocutorsThere 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 criticalBody 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 FrequencyWord StressConsonants, including high functional load consonants, aspiration and final consonants with grammatical meaningVowel lengthening and vowel qualityWeak forms and fast speech phenomena (for listening)Potential for penalty, Probability of offense, and Lexical importanceKey vocabulary for speaking needs

Processing constraintsSentence FocusWord StressWeak forms and fast speech phenomena (for listening, especially in ESL contexts)LearnabilitySentence focusGeneral speaking habits

The PowerPoint slides for this talk will be available after March 26 at

jlevis.public.iastate.edu/intelligibility.ppt

ReferencesBradlow, 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.Field, J. (2005). Intelligibility and the listener. The role of lexical stress. TESOL Quarterly, 39 (3): 399-423.Firth, S. (1992). Pronunciation syllabus design: A question of focus. In Teaching American English pronunciation, Oxford University Press, pp. 173-183.

Hahn, L. (2004). Primary stress and intelligibility: Research to motivate the teaching of suprasegmentals. TESOL Quarterly, 38 (2): 201-223.Jenkins, J. (2002). A sociolinguistically-based, empirically-researched pronunciation syllabus for teaching English as an international language. Applied Linguistics, 23: 83-103.Levis, J. (1999). The intonation and meaning of normal yes-no questions. World Englishes, 18 (3): 373-380.Lippi-Green, R. (1997). English with an accent. Routledge.McNerny, M. & Mendelsohn, D. (1992). Suprasegmentals in the pronunciation class: Setting priorities. In Teaching American English pronunciation, Oxford University Press, pp. 185-196.Munro, M. (2003). A primer on accent discrimination in the Canadian context. TESL Canada Journal, 20 (2): 38-51.Munro, M. & Derwing, T. 1999. Foreign accent, comprehensibility, and intelligibility in the speech of second language learners. Language Learning, 49 (supp. 1): 285-310.Munro, M. & Derwing, T. (2006). The functional load principle in ESL pronunciation instruction: An exploratory study. System, 34: 520-531.

Nation, I. S. P. (1990). Teaching and learning vocabulary. Newbury House.Pennington, M. & Ellis, N. (2000). Cantonese speakers memory for English sentences with prosodic cues. Modern Language Journal, 84 (3): 372-389.Pickering, L. (2006). Current research on intelligibility of English as a lingua franca. Annual Review of Applied Linguistics, 26: 219-233.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.Zielinski, B. (2006). The intelligibility cocktail: An interaction between listener and speaker ingredients. Prospect: An Australian Journal of TESOL, 21 (1): 22-45.

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