One challenge for theories of word recognition is to determine

how the listener recovers the intended lexical segmentation in continuous speech. We argue that syllable structure provides one source of constraint on lexical segmentation and more precisely, that syllable onsets constitute potential alignment points for the mapping process. We present an overview of several studies using explicit syllable segmentation tasks, word spotting and crossmodal priming, which support the hypothesis

Content, Alain

Dumay, Nicolas

Frauenfelder, Uli

English

Frauenfelder, Uli H

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The role of syllable structure in lexical segmentation: Helping listeners avoid mondegreens

Kent Academic Repository

THE ROLE OF SYLLABLE STRUCTURE IN LEXICAL SEGMENTATION:HELPING LISTENERS AVOID MONDEGREENSAlain Content, Nicolas DumayLaboratoire de Psychologie Expérimentale, Université libre de Bruxelles, Belgiqueand Uli H. FrauenfelderLaboratoire de Psycholinguistique Expérimentale, Université de Genève, SuisseABSTRACTOne challenge for theories of word recognition is to de-termine how the listener recovers the intended lexicalsegmentation in continuous speech. We argue that sylla-ble structure provides one source of constraint on lexicalsegmentation and more precisely, that syllable onsetsconstitute potential alignment points for the mappingprocess. We present an overview of several studies usingexplicit syllable segmentation tasks, word spotting andcrossmodal priming, which support the hypothesis.1. INTRODUCTION“Surely you've heard of mondegreens — mishearings ofcommon words and phrases that make their way intospeech.  It was a British writer in the mid-1950s whoadmitted that she misheardThey have slain the Earl of MorayAnd laid him on the greenas And Lady Mondegreen.  She could never figure outwhat poor Lady Mondegreen did for someone to slayher.”[1] “Sadly,” the article concludes, “mondegreendoes not appear in the Bank of English – yet.”In substance, the general argument of this paper isthat syllable structure may help listeners avoid monde-greening every sentence they hear. More specifically, weargue that syllable onsets are generally highly salient inthe signal, and serve as potential alignment points for thelexical search process. The Syllable Onset SegmentationHypothesis (SOSH) bears some close similarity to theMetrical Segmentation Strategy (MSS) proposed forEnglish [2] and contrasts with alternative proposals [3]which assume that the signal is recoded and categorizedprelexically in terms of syllable-sized units mediatinglexical access. We assume that the lexical mappingprocess is based on smaller-size units (phonemes orfeatures), but that syllable structure determinesprivileged alignment points.We present an overview of three sets of studiesbearing on explicit syllabification, on the influence ofsyllable/word misalignments on online measures of lexi-cal access, and on resyllabification at word boundaries.2. EXPLICIT SYLLABIFICATIONOne data source about segmentation comes from explicitsyllabification tasks. In a study investigating adults’syllabification [4], American subjects were required toreverse the syllables in bisyllabic words with singleintervocalic consonants. The listeners’ performance wasnot consistent, the intervocalic consonant beingsometimes placed in the first syllable (melon reversed aslon-me), and sometimes in the second (melon > on-mel).In addition, there were also many ambisyllabic responseswhere the consonant was placed in both syllables (lon-mel). The more sonorous the consonant, the greater theprobability that it was placed in the first syllable ratherthan in the second syllable, and that it would elicitambisyllabic responses.Some years ago, we launched a similar investigationof syllabification in French [5]. Our first study aimed atassessing the syllabification of singleton intervocalicconsonants, and followed closely Treiman & Danis.Much to our surprise, we observed that as the Americanparticipants, French listeners produced about 15% ofambisyllabic responses. We reasoned that such unex-pected responses could occur if decisions about syllableonsets (henceforth marked by an opening square bracket,“[”) and syllable offsets (“]”) involve distinct processes.Follow-up experiments used slightly different tasks, inwhich different groups of participants had to repeateither the first or the second part of the same stimuluswords. As shown in Figure 1, the vast majority ofsecond-part responses included the intervocalicconsonant (e.g. ballon > lon, i.e.[CV), as predicted by allphonological analyses of French. But first-part responsessplit nearly evenly between CV and CVC (ballon > ba orbal). Moreover, the tendency to produce closed (CVC)first-part responses was more manifest for moresonorous consonants, and also influenced byorthographic gemination (e.g. ballon vs palais).In another study [6],  we examined the influence oforthography more directly by comparing syllabificationpreferences in five-year-old nonreaders and ten-year-oldliterate children, using a task, design and materials simi-lar to the previous adult experiment. In the readersgroup, CVC first-part responses were more frequent fororthographically geminated words than for words with asingle orthographic consonant. No such spelling effectemerged for prereaders. Otherwise, in both age groups,the pattern of responses closely replicated the adult dataregarding the dissociation between first and second-partresponses, and the specific effect of sonority on first-partresponses. Thus, it does not seem that this dissociation isdue to the influence of literacy acquisition.We also examined syllabification by AmericanEnglish speakers in Brussels. The experiment and mate-rials were designed exactly as in the French study de-scribed above, but we also contrasted first and secondsyllable-stressed words. For second-syllable stressedstimuli, the pattern closely resembles the French data:more than 90% of CV[CV responses for the onset of thesecond part, and a lot of variability for the offset of thefirst part. For the first-syllable stress words however, adifferent pattern was observed, suggesting a CVC][V syl-labification: First-syllable responses nearly always in-cluded the intervocalic consonant and about 30% of sec-ond-syllable responses for words with a single ortho-graphic consonant did not include the consonant.Overall, these findings indicate that French listenersare not consistent in their segmentation of syllables,specially for syllable offsets. Interestingly, by separatingthose responses that required the determination of thesyllable onsets from those requiring decisions for sylla-ble offsets, we observed a clear dissociation. The formerwere more consistent than the latter; second syllableresponses nearly always began with the consonant,whereas responses for the first syllable varied more, of-ten including the intervocalic consonant.3. ON WORD-SYLLABLE MISALIGNMENTWe take the syllabification data to indicate that syllableonsets constitute reliable segmentation points in the sig-nal, and we hypothesize that syllable onsets are used asprivileged alignment points for lexical search in continu-ous speech recognition. In further studies, we have triedto address this issue by investigating the processing ofwords embedded in multisyllabic carriers. We examinedwhether a misalignment between a syllable onset and thetarget word onset delays the recognition of the word.3.1. Word SpottingSome empirical support for SOSH comes from a wordspotting experiment [7] in which participants madespeeded manual responses when they detected monosyl-labic words embedded at the beginning or end of bisyl-labic nonwords (e.g., lac in lactuf or zunlac). All targetwords began with a liquid and ended with an occlusive.Syllable structure was manipulated by varying the con-sonant immediately preceding or following the targetword. Thus, our manipulation relied on generally ac-cepted phonotactic principles for French consonantclusters, which state that obstruent-liquid clusters aretautosyllabic (as in la.cluf or zu.glac), whereas obstruent-obstruent, liquid-liquid and nasal-liquid clusters areseparated (as in lac.tuf or zun.lac). All consonant clustersused were attested in French polysyllabic words. Twogroups were tested, one with the onset alignment and theother with the offset alignment manipulation.According to SO S H , the lexical cost due toword/syllable misalignment should be greater for finalembedding, which corresponds to onset misalignment,than for initial embedding. As shown in Figure 2, thisprediction was confirmed both by RT and error data.Onset misalignment (zu[glac vs. zun[lac) induced sig-nificant RT (74 msec) and error (7.3%) effects, whereasoffset misalignment (la]cluf vs lac]tuf) revealed only asmall and non-significant RT effect.3.2 Crossmodal Repetition PrimingAnother study conducted by Gregory Leclercq in Brus-sels used cross-modal repetition priming. Participantshad to perform a lexical decision task on visuallypresented monosyllabic words, preceded by a related orunrelated bisyllabic auditory nonword. Visual targetitems were presented for 50 msec, and synchronized withthe offsets of the auditory stimulus.In the related pairs, the auditory prime word was em-bedded in a bisyllabic nonword carrier. We contrastedfour related conditions, in a design similar to the previ-ous word-spotting experiment. Prime words were em-bedded either at the beginning or at the end of the carri-ers, and syllable structure was manipulated by varyingthe nature of the consonant immediately preceding orfollowing the target word. Thus nam.robe, ja.vrobe,rob.jaf  and ro.blane were the four possible relatedprimes for the visual target ROBE. Different groups ofparticipants were tested with initial and final prime em-bedding positions.Based on SOSH, we predicted that listeners shouldshow greater sensitivity to onset (final embedding,nam.robe vs ja.vrobe) than to offset misalignment. Afirst analysis of the results did not seem to confirm ourexpectations. As shown in Figure 3, when the data werecollapsed for both blocks together, no hint of thepredicted interaction was observed. In fact, a significantrelatedness by alignment interaction was found, but it didnot vary as a function of position. However a differentPart 1 Part 200.10.20.30.40.50.60.70.80.91Prop CV responsesConditionliquidsnasalsfricativesplosivesFigure 1. Proportion of canonical syllabification responses(CV]CV for Part 1 and CV[CV for Part 2).Misaligned Aligned300400700800Final EmbeddingInitial Embedding05101520Figure 2. Word spotting RTs (circles) and Errors (squares).picture emerged when we looked at the data for Block 1only. As shown in Figure 4, results for Block 1 conformexactly to our predictions: A significant alignment effectwas only observed for the final embedding condition.Although these data are clearly preliminary, and furthertesting is needed to confirm the outcome, they provide atleast encouraging support for our hypothesis.4. ON RESYLLABIFICATIONObviously the interest of SOSH for continuous wordrecognition depends on the likelihood that word andsyllable onsets coincide. Paradoxically, given theprocessing costs observed in the previous experiments,SOSH would be a hindrance rather than an aid ifmisalignments are the rule in continuous speech.One reason such misalignment might be frequent isresyllabification. Since syllables pertain to the domain ofsuprasegmental structure, it is generally admitted thatsyllable reorganisations occur  at word junctures (as il-lustrated by the “laid him on” / “Lady Mon” anecdote).Accordingly, some models of speech production [8] pro-pose that phonetic encoding involves syllabic articula-tory plans computed or accessed after word boundarieshave been erased and resyllabification has occurred.It thus seemed critical to assess whether suchphonetic resyllabification does indeed occur. To that end,we constructed pairs of two-word phrases that had twosyllables in common but differed by the position of theword boundary (e.g. tant#rou in une tante roublarde,tan#trou in des temps troublants, see [9]). Acrossvarious experiments, the consonant cluster at the wordjuncture was either obstruent+liquid (OB L I ) or/s/+obstruent (SOB). These materials were used toinvestigate several related issues: (1) whether the lexicalintent of speakers determines systematic phonetic varia-tions; (2) whether listeners are sensitive to such variationin a syllabification task; and (3) whether it affects lexicalprocessing.In the production study, naive French speakers pro-duced pairs of such two-word phrases, either in isolation,or in sentence context. Durational analyses showed sys-tematic lengthening of the pre-boundary vowel and ofthe liquid consonant in CVC#CV sequences. In contrast,no reliable effects were obtained for SOB clusters.For the perceptual studies, the shared bisyllabic se-quences (e.g. tantrou) were extracted from the OBLInoun phrases. In one study, participants were asked torepeat either the first or second syllable of the sequencesunder time pressure, and we examined the pattern ofsyllabification. As shown in Figure 5, the proportion ofcanonical syllabification responses (CV][CCV) is muchhigher for the second syllable repetition condition thanfor the first syllable repetition condition, thus replicatingthe findings described above. In addition, and more im-portantly, syllabification responses indeed reflect  themanipulation of word boundary position.In another study [9], the same stimuli were used in aword spotting task. Participants detected CVC words ei-ther at the beginning (tante in tantrou) or at the end (e.g.roche in icroche) of nonsense bisyllables. Whereas noeffect was observed for SOB clusters, significant phoneticmisalignment effects occurred for OBLI clusters: Listen-ers were about 100 msec faster to detect roche  ini#croche than in ic#roche; and they were 140 msec fasterto detect tante in  tant#rou than in tan#trou. The findingof an offset misalignment effect in the latter case appearsto run counter the prediction of SOSH. However, otherdata [10] show that this effect is caused by competitionrelated to the lexical status of the second syllable.In sum, these results run counter the view that inproduction syllable structure is superimposed on thephonological string independently of word junctureinformation. At least for OBLI clusters, we found thatsystematic phonetic variations occur at word boundariesand that listeners are indeed sensitive to them. Theabsence of any word boundary cues in SOB clusters isintriguing. However, it fits well with other syllabificationand production data [11, 12] suggesting that /s/ has aspecial status as regards syllabification or can beconsidered extra-syllabic in such sequences.In the course of our examination of resyllabification,we have started examining in detail the phonetics ofword boundary phonemes. One might wonder whetherthe phonetic cues that we have identified subserve syl-labification, or constitute independent cues to lexicalsegmentation. One radical interpretation of our results isthat resyllabification does not occur: e.g. tan#trou isrealised tan.trou and tant#rou  is realised tant.rou:Misaligned Aligned550570590610630650LDT(msec)InitialFinalFigure 3. Mean Lexical Decision Times in the RelatedConditions, as function of the position of the embedded primeword in the carrier, and of syllable structure.Misaligned Aligned530550570590610630LDT (msec)Figure 4. Mean Lexical Decision Times for first target pres-entation (Block 1) in the Related Conditions.perceptually, phonetic cues inform syllabification, andsyllabification informs lexical segmentation. In thisperspective, the absence of phonetic variation in SOBclusters simply means that the two potentialsyllabification of SOB clusters are not phoneticallymarked, e.g.  ra.stu does not differ phonetically fromras.tu. Of course, it remains to be determined whetherphonetic cues distinguish Lady Mon from laid him on.5. CONCLUSIONSSOSH is based on two ideas: onsets, relative to offsetsconstitute more reliable segmentation points; syllableboundaries tend to coincide with word boundaries. Re-garding the first claim, there is much phonological evi-dence that indicates that word/syllable initial consonantare more salient, more stable both in terms of theirphonetic characteristics but also in terms of languagechange. With respect to the second claim, the correspon-dence of word and syllable onsets has prima facie value.The notion of syllable has a long history in phonologyand phonetics. It is one of those ubiquitous notions thateveryone endorses but no one can define. Nevertheless,some of the major theories define syllable boundaries onphonotactic grounds, that is, from attested word onsetsand offsets. While the phonotactic perspective may notcapture all the phonological facts, it definitely suggeststhat overall, word and syllable boundaries should corre-spond, except for special cases such as liaison, orenchaînement. The frequency and phonetic characteris-tics of such phenomena require further examinationPerhaps the most interesting implication of SOSHconcerns the issue of language specificity. Indeed thesimilarity between our results and other findings inDutch and English, and the close relation between SOSHand MSS suggests that the syllable’s role might be moresimilar across languages than has generally been admit-ted. The universal status of SOSH is thus open to inves-tigation. Another issue is how syllable structure com-bines with other bottom-up and top-down segmentationcues. We have started to examine how SOSH and compe-tition interact [10].  It remains for further research todetermine the respective roles of syllable structure,rhythmic and prosodic cues, and word knowledge inlexical segmentation.While further supporting evidence would certainlyhelp the cause of SOSH, we would argue that it consti-tutes a more plausible and more viable hypothesis thanthe prelexical syllabic classification hypothesis, and thatit opens interesting avenues for further research.6. ACKNOWLEDGEMENTSThis research is supported by grants from the Com-munauté française de Belgique (A.R.C. 96/01-203) andfrom the Swiss FNRS (Project 1113-049698.96). Wethank Cécile Fougeron for her comments and many use-ful discussions. Nicolas Dumay is research assistant atthe Belgian FNRS. Correspondence to Alain Content,LAPSE—ULB CP191, Avenue F. D. Roosevelt, 50,B–1050 Bruxelles. Email: Alain.Content@ulb.ac.be.7. REFERENCES[1] Wordwatch (2000). Firstable and other mondegreens,http://titania.cobuild.collins.co.uk/cgi-bin/wwatchlook.[2] Cutler, A., & Norris, D. (1988). The role of strongsyllables in segmentation for lexical access. Journal ofExperimental Psychology : Human Perception andPerformance, 14, 113-121.[3] Segui, J., Dupoux, E., & Mehler, J. (1990). The roleof the syllable in speech segmentation, phoneme identi-fication and lexical access. In G. Altmann (Ed.), Cogni-tive Models of Speech Processing, MIT Press,  263-280.[4] Treiman, R., & Danis, C. (1988). Syllabification ofintervocalic consonants. Journal of Memory andLanguage, 27, 87-104.[5] Content, A., Kearns, R., & Frauenfelder, U. (1999).Boundaries versus onsets in syllabic segmentation. Mssubmitted for publication.[6] Content, A., Frauenfelder, U., & Dumay, N. (1999).Segmentation syllabique chez l'enfant, Journées d'EtudesLinguistiques - La syllabe. Université de Nantes, 69-74.[7] Dumay, N., Banel, M. H., Frauenfelder, U., &Content, A. (1998). Le rôle de la syllabe: segmentationlexicale ou classification? Actes des XXIIèmes journéesd'étude sur la parole, 33-36.[8] Levelt, W., & Wheeldon, L. (1994) Do speakers haveaccess to a mental syllabary? Cognition, 50, 239-269.[9] Dumay, N., Frauenfelder, U., & Content, A. (1999).Acoustic-phonetic cues to word boundary location:evidence from word spotting, Proceedings of ICPhS, SanFrancisco, CA, 281-284.[10] Dumay, N., Frauenfelder, U., & Content, A. (2000).Acoustic-phonetic cues and lexical competition insegmentation of continuous speech. Proceedings ofSWAP, Nijmegen:MPI for Psycholinguistics.[11] Rialland, A. (1994). The phonology and phoneticsof extrasyllabicity in French. In P. A. Keating (Ed.),Phonological structure and phonetic form: Papers inLaboratory Phonology (Vol. 3), 136-159.[12] Treiman, R., Gross, J., & Cwikiel-Glavin, A.(1992). The syllabification of /s/ clusters in English.Journal of Phonetics, 20, 383-402.C#C #CC0.30.40.50.70.80.9CV.CCV responsesPart 1Part 2Figure 5. The effect of word boundaries on syllabification.

Acoustic-phonetic cues and lexical competition in segmentation of continuous speech.

Acoustic-phonetic cues to word boundary location: evidence from word spotting,

Boundaries versus onsets in syllabic segmentation. Ms submitted for publication.

Do speakers have access to a mental syllabary?

Le rôle de la syllabe: segmentation lexicale ou classification? Actes des XXIIèmes journées d'étude sur la parole,

Segmentation syllabique chez l'enfant,

Syllabification of intervocalic consonants.

The phonology and phonetics of extrasyllabicity in French. In

The role of strong syllables in segmentation for lexical access.

The role of the syllable in speech segmentation, phoneme identification and lexical access.

The syllabification of /s/ clusters in English.

The role of syllable structure in lexical segmentation: Helping listeners avoid mondegreens.

One challenge for theories of word recognition is to determine how the listener recovers the intended lexical segmentation in continuous speech. We argue that syllable structure provides one source of constraint on lexical segmentation and more precisely, that syllable onsets constitute potential alignment points for the mapping process. We present an overview of several studies using explicit syllable segmentation tasks, word spotting and crossmodal priming, which support the hypothesis

Frauenfelder, Ulrich Hans

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The role of syllable structure in lexical segmentation: Helping listeners avoid mondegreens.

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