Neural Dynamics of Phonetic Trading Relations for Variable-Rate CV Syllables

The perception of CV syllables exhibits a trading relationship between voice onset time (VOT) of a consonant and duration of a vowel. Percepts of [ba] and [wa] can, for example, depend on the durations of the consonant and vowel segments, with an increase in the duration of the subsequent vowel switching the percept of the preceding consonant from [w] to [b]. A neural model, called PHONET, is proposed to account for these findings. In the model, C and V inputs are filtered by parallel auditory streams that respond preferentially to transient and sustained properties of the acoustic signal, as in vision. These streams are represented by working memories that adjust their processing rates to cope with variable acoustic input rates. More rapid transient inputs can cause greater activation of the transient stream which, in turn, can automatically gain control the processing rate in the sustained stream. An invariant percept obtains when the relative activations of C and V representations in the two streams remain uncha.nged. The trading relation may be simulated as a result of how different experimental manipulations affect this ratio. It is suggested that the brain can use duration of a subsequent vowel to make the [b]/[w] distinction because the speech code is a resonant event that emerges between working mernory activation patterns and the nodes that categorize them.Advanced Research Projects Agency (90-0083); Air Force Office of Scientific Reseearch (F19620-92-J-0225); Pacific Sierra Research Corporation (91-6075-2

Which phonetic features should pronunciation Instructions focus on? An evaluation on the accentedness of segmental/syllable errors in L2 speech

Many English language instructors are reluctant to incorporate pronunciation instruction into their teaching curriculum (Thomson 2014). One reason for such reluctance is that L2 pronunciation errors are numerous, and there is not enough time for teachers to address all of them (Munro and Derwing 2006; Thomson 2014). The current study aims to help language teachers set priorities for their instruction by identifying the segmental and structural aspects of pronunciation that are most foreign-accented to native speakers of American English. The current study employed a perception experiment. 100 speech samples selected from the Speech Accent Archive (Weinberger 2016) were presented to 110 native American English listeners who listened to and rated the foreign accentedness of each sample on a 9-point rating scale. 20 of these samples portray no segmental or syllable structure L2 errors. The other 80 samples contain a single consonant, vowel, or syllable structure L2 error. The backgrounds of the speakers of these samples came from 52 different native languages. Global prosody of each sample was controlled for by comparing its F0 contour and duration to a native English sample using the Dynamic Time Warping method (Giorgino 2009). The results show that 1) L2 consonant errors in general are judged to be more accented than vowel or syllable structure errors; 2) phonological environment affects accent perception, 3) occurrences of non-English consonants always lead to higher accentedness ratings; 4) among L2 syllable errors, vowel epenthesis is judged to be as accented as consonant substitutions, while deletion is judged to be less accented or not accented at all. The current study, therefore, recommends that language instructors attend to consonant errors in L2 speech while taking into consideration their respective phonological environments

Rate Effects on German Unstressed Syllables

German is characterized by the rhythmic alternation of strong and weak syllables. Weak syllables contain short or reduced vowels like schwa. In some instances, the unstressed weak syllable nucleus can be the only difference between words that underlyingly contain a consonant cluster. Examples in German are Kannen 'cans, pitchers' contrasting with kann 'can (V)' or beraten 'to advise' contrasting with braten 'to fry'. In some instances, in a faster rate of speech for example, weakening of the unstressed syllable nucleus is observed which can eventually result in the neutralization between such pairs of words. In slower speech, one might find an opposite effect, that is the appearance of vocalic traces between the members of an underlying consonant cluster. This transition vowel can perceptually cause a confusion in these "minimal pairs". Based on acoustic measurements, I will argue that gestural reorganization can best account for both of these rate effects found in German

What information is necessary for speech categorization? Harnessing variability in the speech signal by integrating cues computed relative to expectations

This is the author's accepted manuscript. This article may not exactly replicate the final version published in the APA journal. It is not the copy of record. The original publication is available at http://psycnet.apa.org/index.cfm?fa=search.displayrecord&uid=2011-05323-001.Most theories of categorization emphasize how continuous perceptual information is mapped to categories. However, equally important are the informational assumptions of a model, the type of information subserving this mapping. This is crucial in speech perception where the signal is variable and context dependent. This study assessed the informational assumptions of several models of speech categorization, in particular, the number of cues that are the basis of categorization and whether these cues represent the input veridically or have undergone compensation. We collected a corpus of 2,880 fricative productions (Jongman, Wayland, & Wong, 2000) spanning many talker and vowel contexts and measured 24 cues for each. A subset was also presented to listeners in an 8AFC phoneme categorization task. We then trained a common classification model based on logistic regression to categorize the fricative from the cue values and manipulated the information in the training set to contrast (a) models based on a small number of invariant cues, (b) models using all cues without compensation, and (c) models in which cues underwent compensation for contextual factors. Compensation was modeled by computing cues relative to expectations (C-CuRE), a new approach to compensation that preserves fine-grained detail in the signal. Only the compensation model achieved a similar accuracy to listeners and showed the same effects of context. Thus, even simple categorization metrics can overcome the variability in speech when sufficient information is available and compensation schemes like C-CuRE are employed

Short-term exposure alters adult listeners’ perception of segmental phonotactics

This study evaluates the malleability of adults' perception of probabilistic phonotactic (biphone) probabilities, building on a body of literature on statistical phonotactic learning. It was first replicated that listeners categorize phonetic continua as sounds that create higher-probability sequences in their native language. Listeners were also exposed to skewed distributions of biphone contexts, which resulted in the enhancement or reversal of these effects. Thus, listeners dynamically update biphone probabilities (BPs) and bring this to bear on perception of ambiguous acoustic information. These effects can override long-term BP effects rooted in native language experience

Liaison acquisition: debates, critical issues, future research

International audienceLiaison is a sandhi phenomenon in French. Over the last four decades, it has given rise to many different models illustrating the whole range of phonological theories. More recently, new studies have documented its acquisition in French-speaking children as well as adult learners of French as a second language. These studies have resulted in the elaboration of two models of the acquisition process: 1/ the constructionist model (Chevrot, Dugua & Fayol, 2009; Nicoladis & Paradis, 2011) developed within the framework of the usage-based theories; 2/ the phonological model (Wauquier, 2009) which represents the framework of nonlinear phonology. Our aim is to re-examine the usage-based model in the light of the criticisms and suggestions made by Wauquier (2009). We shall first present the two models and then examine the issues under discussion. After that, we shall present longitudinal data testing a prediction made by the phonological model with regard to the generalization process in L1 and L2 acquisition. To conclude, we shall identify the points that remain to be clarified for each of the models and the directions which future research should take

Asymmetries in English Vowel Perception Mirror Compression Effects

A series of vowel-identification experiments using gated consonant stimuli shows that English listeners are capable of recovering the vocalic context in which a consonant appears from information contained in the consonant alone. This is true for most consonants tested, including liquids, nasals, and stops in onset and coda position. Positional asymmetries in vowel sensitivity go in opposite directions for liquids (coda sensitivity \u3e onset) and stops (onset \u3e coda). Nasals pattern with liquids in terms of vowel sensitivity from consonant steady states alone, but pattern more closely with stops when portions outside the steady-state are taken into account. It is argued that these asymmetries are related to patterns of cluster-driven vowel compression (also called ‘compensatory shortening’) in speech production

The phonetics and phonology of some syllabic consonants in southern british english

This article presents new experimental data on the phonetics of syllabic /l/ and syllabic /n/ in Southern British English and then proposes a new phonological account of their behaviour. Previous analyses (Chomsky and Halle 1968:354, Gimson 1989, Gussmann 1991 and Wells 1995) have proposed that syllabic /l/ and syllabic /n/ should be analysed in a uniform manner. Data presented here, however, shows that syllabic /l/ and syllabic /n/ behave in very different ways, and in light of this, a unitary analysis is not justified. Instead, a proposal is made that syllabic /l/ and syllabic /n/ have different phonological structures, and that these different phonological structures explain their different phonetic behaviours. This article is organised as follows: First a general background is given to the phenomenon of syllabic consonants both cross linguistically and specifically in Southern British English. In §3 a set of experiments designed to elicit syllabic consonants are described and in §4 the results of these experiments are presented. §5 contains a discussion on data published by earlier authors concerning syllabic consonants in English. In §6 a theoretical phonological framework is set out, and in §7 the results of the experiments are analysed in the light of this framework. In the concluding section, some outstanding issues are addressed and several areas for further research are suggested

Individual Differences in Non-Native Phonological Contrast Learning: The Role of Perceptual Sensitivity to Sub-Phonemic Variation in Native Categories

The current study explored individual differences in sensitivity to sub-phonemic variation of acoustic cues in the perception of a native language (L1) category in order to test the hypothesis that second language (L2) learners’ different sensitivity to the L2-relevant acoustic dimension in L1 perception could explain individual variability in nonnative phonological contrast learning. In addition, this study also investigated whether the modified High Variability Phonetic Training (HVPT) paradigm could aid in nonnative phonological contrast learning. The cue-attention switching training was added to the typical HVPT paradigm with multiple talkers, expecting to reallocate learners’ attention away from the less relevant acoustic dimension to the more informative acoustic dimension in the perception of the target nonnative contrast(s). The present study targeted two groups of learners with different L1 backgrounds: naïve adult English learners of Korean and intermediate adult Korean learners of English. The multiple HVPT sessions trained English learners of Korean on a Korean three-way laryngeal contrast in stop (/p’/-/p/-/ph/) and trained Korean learners of English on three English vowel contrasts, /i/-/ɪ/, /ɛ/-/æ/, and /ʊ/ -/u/.The Visual Analogue Scaling (VAS) task measured English adult listeners’ sensitivity to sub-phonemic acoustic details in the perception of English stop voicing contrast with a stimuli continuum of English voiced and voiceless stops (/b/-/p/) varying in VOT and f0 at vowel onset. For Korean adult listeners, the AXB oddity task quantified learners’ sensitivity to within-category differences induced by spectral and duration cue changes, using a set of stimuli belonging to the Korean /i/ vowel but with different spectral and duration properties. The results of the HVPT training in experiments 1 and 3 revealed that in both groups, L2 learners with higher sensitivity to L2-relevant acoustic cues in L1 perception had an initial advantage in L2 contrast learning and showed more nativelike cue utilization during and after the HVPT. On the other hand, learners with less sensitivity to the “right” acoustic cues failed to systematically use those cues in perceiving the target L2 contrast(s). Learners who received the modified HVPT with the cue-attention switching training with L1 stimuli in experiments 2 and 4 demonstrated more native-like use of acoustic cues in L2 perception than learners who received only the typical HVPT with multiple talkers. English learners of Korean with relatively less sensitivity to f0 cues in the perception of English voicing contrast performed similarly to those with relatively high sensitivity to f0 cues. For Korean learners of English, the benefit of the cue-attention switching training was observed in learning the English /i/-/ɪ/ contrast, but not in more challenging /ɛ/-/æ/ and /ʊ/ -/u/ contrasts. Korean learners of English with the cue-attention switching training showed more reliance on spectral than duration cues like English native listeners. This study showed the relation between individual differences in sensitivity to sub-phonemic acoustic details in L1 and the nonnative novel phonological contrast learning and a possible type of training to overcome disadvantages due to the individual differences. The results suggest the transfer of L1 cue sensitivity to L2 cue utilization. That is, how successfully L2 learners progress to become more nativelike listeners can be predicted in terms of to what degree they have sensitivity to the L2 informative acoustic cue in L1 speech perception. This implies that individual differences in the L2-relevant cue sensitivity may determine the initial stage of learning and to what extent learners can benefit from L2 training. Moreover, this study emphasizes the importance of considering individual differences to predict L2 learners’ learning outcomes and provide appropriate L2 training to learners whose perceptual abilities may place them at a disadvantage. The VAS and AXB oddity tasks showed possibilities as pretraining assessments to predict the acquisition of L2 phonological contrasts and L2 cue-weighting strategies