LINGUIST List 24.4504

Tue Nov 12 2013

Review: Lang. Acquisition; Phonetics; Phonology: Boll-Avetisyan (2012)

Editor for this issue: Joseph Salmons <jsalmonslinguistlist.org>



Date: 01-Sep-2013
From: Kevin Mendousse <k.mendousseauckland.ac.nz>
Subject: Phonotactics and Its Acquisition, Representation, and Use
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Book announced at http://linguistlist.org/issues/23/23-4864.html

AUTHOR: Natalie Boll-AvetisyanTITLE: Phonotactics and Its Acquisition, Representation, and UseSUBTITLE: An Experimental-Phonological StudySERIES TITLE: LOT dissertation seriesPUBLISHER: Netherlands Graduate School of Linguistics / Landelijke (LOT)YEAR: 2012

REVIEWER: Kevin Mendousse, University of Auckland

SUMMARYAs indicated in the Acknowledgements (pp. xi-xiv), Phonotactics and ItsAcquisition, Representation, and Use: An Experimental-Phonological Studyoriginated as a PhD dissertation completed at Utrecht University, Netherlands,under the supervision of René Kager. The study addresses a range of issues onthe acquisition and representation of phonotactic knowledge and how suchknowledge is put to use in speech processing; it will be of particularinterest to phonologists and psycholinguists working in the areas of speechsegmentation and lexical acquisition.

Within the first opening paragraphs of Chapter 1, “General Introduction” (pp.1-16), both the purpose of the proposed study and its rationale are set out.No language allows for a random combination of phonemes within words, and itis well established that co-occurrence (im)possibilities between phonemes aregoverned by language-specific constraints, i.e. phonotactic constraints.Speakers of natural languages all possess reliable -- albeit mostly implicit-- knowledge of such constraints, hence our ability to intuitivelydiscriminate between plausible and implausible combinations of phonemes inboth L1 and L2 (L2 phonotactic knowledge improving with advanced L2proficiency). Unlike orthographic systems, however, the speech signal iscontinuous and lacks well-defined cues to word boundaries, so how do listenersnonetheless succeed in the seemingly effortless task of breaking down theacoustic signal into lexical and sub-lexical units to access the words storedin their mental lexicon? If lexical recognition were a prerequisite to speechsegmentation, language-learning infants, who lack lexical knowledge at theonset, would logically be unable to initiate speech segmentation. Hence theauthor’s hypotheses: speech segmentation must precede lexical acquisition; andspeakers must rely on cues other than lexical information in order to identifyword boundaries when processing speech. What these cues are and how they areused to facilitate speech segmentation and lexical acquisition is preciselythe subject matter of the proposed investigation. To this end, the authorprovides a brief review of literature on the form of phonotacticrepresentations in use as well as on the acquisition and source of phonotacticknowledge, highlighting in particular the need to shed light on the followingquestions: a) Can complex phonotactic representations such as OCP-Place -- atypologically well-attested constraint within words restricting theco-occurrence of non-adjacent homorganic consonants by extending acrossintervening vowels -- facilitate speech segmentation and lexical acquisition?b) Is the use of OCP-Place language-specific, and therefore acquired from theinput, or due to some innate universal perceptual bias? c) If acquired, issuch phonotactic knowledge sourced from the lexicon or continuous speech? d)Is the acoustic signal processed by means of a trough- or chunk-basedsegmentation strategy, the former requiring listeners to attend to lowtransitional probabilities, the latter to high transitional probabilities? e)In lexical acquisition, does knowledge of probabilistic phonotactics interactwith knowledge of syllable structure, which is known to affect speechprocessing?

Subsequent chapters, which all form stand-alone studies in their own right,report and comment in detail on both the methodology and results of a seriesof artificial speech segmentation and nonword recall experiments designed toaddress the above issues. Chapter 2, “Does the lexicon bootstrap phonotactics,or vice versa?” (pp. 17-47), showcases an experiment drawing on an artificiallanguage containing trisyllabic /s/-vowel-/s/ sequences, which have a lowprobability of occurrence in Dutch infant-directed continuous speech but areover-represented in the infant-directed lexicon. Data indicate that Dutch L1infants prefer locating word boundaries inside rather than outside suchphonemic clusters. No such segmentation preference, however, was found for/p/-vowel-/p/ sequences, which are over-represented in both continuous speechand the infant-directed lexicon. These results are consistent with atrough-based segmentation strategy, which relies on cues from low probabilitysequences for inserting word boundaries at dips in phoneme transitionalprobability, and suggest that segmentation cues are indeed acquired fromcontinuous speech rather than from the lexicon.

Chapter 3, “OCP-Place in Speech Segmentation” (pp. 49-79), demonstrates thatthe effects of OCP-Place on speech segmentation cannot be said to originatefrom a universal functional bias against the ability to encode separately twoconsonants with a shared place of articulation. Indeed, results from fourartificial language learning experiments indicate that, unlike OCP-Coronal,OCP-Labial is effectively used by adult native listeners of Dutch as a cue forspeech segmentation. The Dutch lexicon is restricted only by the latterconstraint, which suggests that the use of OCP-Place as a segmentation cue inspeech processing is language-specifically correlated with Dutch phonemedistribution and that this constraint is therefore acquired from the input.

Building on the above findings, Chapter 4, “OCP-Place for Speech Processing: ABias on Perception or Acquisition? The Case of Mandarin Chinese” (pp. 81-109),provides supporting evidence of knowledge of OCP-Place as alanguage-specifically acquired constraint. In particular, it shows that,unlike the native Dutch-speaking informants in the previous chapter, MandarinChinese native speakers -- whose lexicon is not restricted by OCP-Place -- donot use this constraint as a speech segmentation cue, as would be predicted ifOCP were due to some universal functional or cognitive bias on acquisition.Further data from three groups of Mandarin Chinese L2 learners of Dutch withvarying language proficiency and geographical learning settings (i.e. advancedL2 learners of Dutch living in the Netherlands, advanced L2 learners of Dutchliving in China, beginning L2 learners of Dutch living in the Netherlands)reveal that OCP-Place is only used as a segmentation cue by advanced L2learners of Dutch who had acquired Dutch in the Netherlands. It follows thatthe acquisition of OCP-Place as a speech segmentation cue in L2 requires bothadvanced L2 proficiency and sufficient L2 exposure to native input.

Chapter 5, “Probabilistic Phonotactics in Lexical Acquisition: The Role ofSyllable Complexity” (pp. 111-137), reports on two experiments with adultmonolingual native speakers of Dutch, designed to assess whether knowledge ofmarkedness constraints on syllables modulates phonotactic probability effectson lexical acquisition. By showing that the facilitory effect of highprobability phonotactics is significantly enhanced in the case of short-termmemory recognition tasks involving more complex syllable structures, resultssuggest that probabilistic phonotactics and structural phonotactic knowledgeas part of a phonological grammar belong to two individual but interactingknowledge components at the sub-lexical level.

Chapter 6, “Second Language Probabilistic Phonotactics and Syllable Structurein Short-Term Memory Recognition” (pp. 139-165), provides further evidence onthe separate storage of the two aforementioned sub-lexical knowledgecomponents by demonstrating that these can be acquired independently of eachother. Indeed, results from a probed recognition task using phonotacticallylegal monosyllabic nonwords manipulated for biphone frequency indicate thatSpanish and Japanese L2 learners of Dutch -- whose L1s allow for less complexsyllable structure than the target language (i.e. CVC in Japanese and CCVC inSpanish vs CCCVCCC in Dutch) -- experienced facilitation of L2 biphonefrequency even in the case of biphone structures unattested in theirrespective L1s. Such knowledge of n-phone probabilities was thus acquiredindependently of their syllable context of occurrence.

Finally, Chapter 7, “General Conclusion” (pp. 167-176), summarizes previouschapters with a focus on integrating their respective findings and discussingtheir overall significance for phonology and developmental psychology. Itfurther addresses a number of issues for future investigation. In particular,the chapter highlights the need to determine whether knowledge of both under-and over-represented phonotactic patterns may, in fact, play different rolesin speech processing: “It might be that under-representations are more usablein speech segmentation, whereas in lexical acquisition, a clear facilitationcomes from knowledge of over-represented patterns” (p. 173). The author alsocalls for research into whether only knowledge of under-representations isacquired from continuous speech in L1 and L2, or if over-representedphonotactic patterns are also acquired in similar fashion.

EVALUATIONOverall, Boll-Avetisyan’s study is as informed and innovative as it isinsightful and thought-provoking. It provides the reader with a deepunderstanding of how complex abstract phonotactic representations are used inspeech segmentation and lexical acquisition, and how these are acquired inboth L1 and L2. The work’s scientific impact and significance rest on a strongbody of empirical evidence collected through creative experimentation, withrobust parameters designed to address original research questions.

As the author notes, despite the vast body of evidence for its role in speechsegmentation and lexical acquisition, “the question of how phonotacticknowledge is actually put to use in speech processing has been heavilyneglected” by researchers (p. 4). The reasons are twofold: on the one hand“psychologists often disregard the nature and complexity of linguisticrepresentations”, focussing instead on the mind’s inner working and learningmechanisms; on the other hand “linguists tend to neglect the consequences ofthe fact that linguistic representations need to be used in speechprocessing”, referring instead to the internal structure and complexity oflinguistic systems (p. 4). Boll-Avetisyan’s research effectively bridges thisgap.

Boll-Avetisyan’s investigation extends both the scope and depth of theliterature on the role of phonotactics in speech segmentation and lexicalacquisition by showing that infants as well as monolingual and L2 adultspeakers draw on phonotactic knowledge of a more abstract and complex naturethan mere n-phone probabilities when segmenting continuous speech. Contrary topredictions made by functionalist theories -- which, as a result of a claimeduniversal bias on perception, predict that listeners can only processsequences of homorganic consonants as separate elements by drawing onadditional information from the lexicon (pp. 171-172) -- , participants usedOCP as a cue for parsing an artificial language stripped of any such lexicalcues. This finding strongly suggests that knowledge of OCP as used in speechsegmentation is language specific and acquired from continuous speech ratherthan from the lexicon.

Moreover, by showing that infants use their knowledge of under- but notover-represented phoneme pairs in speech segmentation, Boll-Avetisyan’s studyprovides new, compelling insight into the informativeness role of phonotacticknowledge for the parsing of continuous speech: phoneme pairs occurring moreoften within words than across word boundaries -- because speech consists of aconcatenation of words -- , there are fewer troughs than peaks in transitionalprobability and so, in short, “it is more useful to attend to relatively fewtroughs than to the much larger number of peaks in transitional probabilitywhen segmenting speech” (p. 172). By further demonstrating that “thefacilitory effect of high probability on lexical acquisition increased withincreasing syllable complexity and vice-versa” (p. 172), Boll-Avetisyan’sresults support the hypothesis that speakers possess two separate butinteracting sub-lexical phonotactic knowledge components, one specialising inprobabilistic phonotactics and the other in structural phonotactics.

Given the complexity of the research undertaken and the statistical toolsused, it is remarkable that the accounts and analyses expounded are alwaysclear, relevant, effective and highly interesting. The author clearly has anoutstanding ability to formulate original, theoretically-informed hypothesesbased on previous literature and to subsequently put these to the test throughcareful experimentation. This, in combination with frequent brief summaryreports and a text written to the highest academic standard -- if we except anumber of typographical and/or grammatical errors/inconsistencies -- , makesthe author's scholarship readily available to the intended readership as wellas to the wider linguistic community.

ABOUT THE REVIEWERDr Kevin Mendousse holds a PhD in linguistics and is currently a SeniorLecturer in the School of European Languages and Literatures at the Universityof Auckland, New Zealand, where he teaches undergraduate and postgraduatecourses in both French language and linguistics. He is the author of a numberof journal articles, conference papers and invited research seminars focusingprimarily on distinctive feature theory and markedness theory, as they applyto the (morpho)phonology of French and/or English, as well as on the historyof linguistic ideas. His research interests also include a forthcoming booktranslation of original linguistic research carried out on the Ua Pou dialectof the Marquesan language.

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