Context effects on second-language learning of tonal contrasts.

Studies of lexical tone  learning generally focus on monosyllabic contexts, while reports of phonetic learning benefits associated with input variability are based largely on experienced learners. This study trained inexperienced learners on Mandarin tonal contrasts to test two hypotheses regarding the influence of context and variability on tone  learning. The first hypothesis was that increased phonetic variability of tones in disyllabic contexts makes initial tone  learning more challenging in disyllabic than monosyllabic words. The second hypothesis was that the learnability of a given tone varies across contexts due to differences in tonal variability. Results of a word learning experiment supported both hypotheses: tones were acquired less successfully in disyllables than in monosyllables, and the relative difficulty of disyllables was closely related to contextual tonal variability. These results indicate limited relevance of monosyllable-based data on Mandarin learning for the disyllabic majority of the Mandarin lexicon. Furthermore, in the short term, variability can diminish learning; its effects are not necessarily beneficial but dependent on acquisition stage and other learner characteristics. These findings thus highlight the importance of considering contextual variability and the interaction between variability and type of learner in the design, interpretation, and application of research on phonetic learning

Intraspeaker Comparisons of Acoustic and Articulatory Variability in American English /r/ Productions

The purpose of this report is to test the hypothesis that speakers utilize an acoustic, rather than articulatory, planning space for speech production. It has been well-documented that many speakers of American English use different tongue configurations to produce /r/ in different phonetic contexts. The acoustic planning hypothesis suggests that although the /r/ configuration varies widely in different contexts, the primary acoustic cue for /r/, a dip in the F3 trajectory, will be less variable due to tradeoffs in articulatory variability, or trading relations, that help maintain a relatively constant F3 trajectory across phonetic contexts. Acoustic data and EMMA articulatory data from seven speakers producing /r/ in different phonetic contexts were analyzed. Visual inspection of the EMMA data at the point of F3 minimum revealed that each speaker appeared to use at least two of three trading relation strategies that would be expected to reduce F3 variability. Articulatory covariance measures confirmed that all seven speakers utilized a trading relation between tongue back height and tongue back horizontal position, six speakers utilized a trading relation between tongue tip height and tongue back height, and the speaker who did not use this latter strategy instead utilized a trading relation between tongue tip height and tongue back horizontal position. Estimates of F3 variability with and without the articulatory covariances indicated that F3 would be much higher for all speakers if the articulatory covariances were not utilized. These conclusions were further supported by a comparison of measured F3 variability to F3 variabilities estimated from the pellet data with and without articulatory covariances. In all subjects, the actual F3 variance was significantly lower than the F3 variance estimated without articulatory covariances, further supporting the conclusion that the articulatory trading relations were being used to reduce F3 variability. Together, these results strongly suggest that the neural control mechanisms underlying speech production make elegant use of trading relations between articulators to maintain a relatively invariant acoustic trace for /r/ across phonetic contexts

Intraspeaker Comparisons of Acoustic and Articulatory Variability in American English /r/ Productions

The purpose of this report is to test the hypothesis that speakers utilize an acoustic, rather than articulatory, planning space for speech production. It has been well-documented that many speakers of American English use different tongue configurations to produce /r/ in different phonetic contexts. The acoustic planning hypothesis suggests that although the /r/ configuration varies widely in different contexts, the primary acoustic cue for /r/, a dip in the F3 trajectory, will be less variable due to tradeoffs in articulatory variability, or trading relations, that help maintain a relatively constant F3 trajectory across phonetic contexts. Acoustic data and EMMA articulatory data from seven speakers producing /r/ in different phonetic contexts were analyzed. Visual inspection of the EMMA data at the point of F3 minimum revealed that each speaker appeared to use at least two of three trading relation strategies that would be expected to reduce F3 variability. Articulatory covariance measures confirmed that all seven speakers utilized a trading relation between tongue back height and tongue back horizontal position, six speakers utilized a trading relation between tongue tip height and tongue back height, and the speaker who did not use this latter strategy instead utilized a trading relation between tongue tip height and tongue back horizontal position. Estimates of F3 variability with and without the articulatory covariances indicated that F3 would be much higher for all speakers if the articulatory covariances were not utilized. These conclusions were further supported by a comparison of measured F3 variability to F3 variabilities estimated from the pellet data with and without articulatory covariances. In all subjects, the actual F3 variance was significantly lower than the F3 variance estimated without articulatory covariances, further supporting the conclusion that the articulatory trading relations were being used to reduce F3 variability. Together, these results strongly suggest that the neural control mechanisms underlying speech production make elegant use of trading relations between articulators to maintain a relatively invariant acoustic trace for /r/ across phonetic contexts

Structured heterogeneity in Scottish stops over the 20th Century

How and why speakers differ in the phonetic implementation of phonological contrasts, and the relationship of this ‘structured heterogeneity’ to language change, has been a key focus over fifty years of variationist sociolinguistics. In phonetics, interest has recently grown in uncovering ‘structured variability’—how speakers can differ greatly in phonetic realization in nonrandom ways—as part of the long-standing goal of understanding variability in speech. The English stop voicing contrast, which combines extensive phonetic variability with phonological stability, provides an ideal setting for an approach to understanding structured variation in the sounds of a community’s language that illuminates both synchrony and diachrony. This article examines the voicing contrast in a vernacular dialect (Glasgow Scots) in spontaneous speech, focusing on individual speaker variability within and across cues, including over time. Speakers differ greatly in the use of each of three phonetic cues to the contrast, while reliably using each one to differentiate voiced and voiceless stops. Interspeaker variability is highly structured: speakers lie along a continuum of use of each cue, as well as correlated use of two cues—voice onset time and closure voicing—along a single axis. Diachronic change occurs along this axis, toward a more aspiration-based and less voicing-based phonetic realization of the contrast, suggesting an important connection between synchronic and diachronic speaker variation

Phonetic convergence in temporal organization during shadowed speech

The goal of this study was to examine phonetic convergence (when one imitates the phonetic characteristics of another talker) in various measures of temporal organization during shadowed speech across different American English dialects. Participants from the Northern and Midland American English dialect regions, plus several "mobile" talkers, were asked to read 72 sentences to establish a baseline for temporal organization, and then to repeat the same 72 sentences after Northern, Midland, and Southern model talkers. Measures of temporal organization (i.e., %V, ΔC, ΔV, rPVI-C, and nPVI-V) were calculated for the read sentences, shadowed sentences, and model talker sentences. Statistical analysis of the differences in distance between the model talker sentences and the shadowers' read and shadowed sentences, respectively, revealed significant convergence by all three shadowing groups toward the model dialects for ΔV, and significant divergence by Mobile talkers away from the model talkers for nPVI-V. Though the result of divergence by Mobile talkers was unexpected, both results provide evidence that support previous studies, which claim that social perception is a large contributing factor in convergence and divergence. These results are also consistent with previous findings demonstrating variation across dialects in temporal organization and, in addition, provide evidence for variation across dialects in convergence in temporal organization.The Ohio State University College of Arts and Sciences Undergraduate Research ScholarshipNo embargoAcademic Major: Linguistic

Phonetic variability and grammatical knowledge: an articulatory study of Korean place assimilation.

The study reported here uses articulatory data to investigate Korean place assimilation of coronal stops followed by labial or velar stops, both within words and across words. The results show that this place-assimilation process is highly variable, both within and across speakers, and is also sensitive to factors such as the place of articulation of the following consonant, the presence of a word boundary and, to some extent, speech rate. Gestures affected by the process are generally reduced categorically (deleted), while sporadic gradient reduction of gestures is also observed. We further compare the results for coronals to our previous findings on the assimilation of labials, discussing implications of the results for grammatical models of phonological/phonetic competence. The results suggest that speakers’ language-particular knowledge of place assimilation has to be relatively detailed and context-sensitive, and has to encode systematic regularities about its obligatory/variable application as well as categorical/gradient realisation

Are words easier to learn from infant- than adult-directed speech? A quantitative corpus-based investigation

We investigate whether infant-directed speech (IDS) could facilitate word form learning when compared to adult-directed speech (ADS). To study this, we examine the distribution of word forms at two levels, acoustic and phonological, using a large database of spontaneous speech in Japanese. At the acoustic level we show that, as has been documented before for phonemes, the realizations of words are more variable and less discriminable in IDS than in ADS. At the phonological level, we find an effect in the opposite direction: the IDS lexicon contains more distinctive words (such as onomatopoeias) than the ADS counterpart. Combining the acoustic and phonological metrics together in a global discriminability score reveals that the bigger separation of lexical categories in the phonological space does not compensate for the opposite effect observed at the acoustic level. As a result, IDS word forms are still globally less discriminable than ADS word forms, even though the effect is numerically small. We discuss the implication of these findings for the view that the functional role of IDS is to improve language learnability.Comment: Draf

A role for the developing lexicon in phonetic category acquisition

Infants segment words from fluent speech during the same period when they are learning phonetic categories, yet accounts of phonetic category acquisition typically ignore information about the words in which sounds appear. We use a Bayesian model to illustrate how feedback from segmented words might constrain phonetic category learning by providing information about which sounds occur together in words. Simulations demonstrate that word-level information can successfully disambiguate overlapping English vowel categories. Learning patterns in the model are shown to parallel human behavior from artificial language learning tasks. These findings point to a central role for the developing lexicon in phonetic category acquisition and provide a framework for incorporating top-down constraints into models of category learning

Sociolinguistic Conditioning of Phonetic Category Realisation in Non-Native Speech

The realisation of phonetic categories reflects a complex relationship between individual phonetic parameters and both linguistic and extra-linguistic conditioning of language usage. The present paper investigates the effect of selected socio-linguistic variables, such as the age, the amount of language use and cultural/social distance in English used by Polish immigrants to the U.S. Individual parameters used in the realisation of the category ‘voice’ have been found to vary in their sensitivity to extra-linguistic factors: while the production of target-like values of all parameters is related to the age, it is the closure duration that is most stable in the correspondence to the age and level of language proficiency. The VOT and vowel duration, on the other hand, prove to be more sensitive to the amount of language use and attitudinal factors

Time and information in perceptual adaptation to speech

Presubmission manuscript and supplementary files (stimuli, stimulus presentation code, data, data analysis code).Perceptual adaptation to a talker enables listeners to efficiently resolve the many-to-many mapping between variable speech acoustics and abstract linguistic representations. However, models of speech perception have not delved into the variety or the quantity of information necessary for successful adaptation, nor how adaptation unfolds over time. In three experiments using speeded classification of spoken words, we explored how the quantity (duration), quality (phonetic detail), and temporal continuity of talker-specific context contribute to facilitating perceptual adaptation to speech. In single- and mixed-talker conditions, listeners identified phonetically-confusable target words in isolation or preceded by carrier phrases of varying lengths and phonetic content, spoken by the same talker as the target word. Word identification was always slower in mixed-talker conditions than single-talker ones. However, interference from talker variability decreased as the duration of preceding speech increased but was not affected by the amount of preceding talker-specific phonetic information. Furthermore, efficiency gains from adaptation depended on temporal continuity between preceding speech and the target word. These results suggest that perceptual adaptation to speech may be understood via models of auditory streaming, where perceptual continuity of an auditory object (e.g., a talker) facilitates allocation of attentional resources, resulting in more efficient perceptual processing.NIH NIDCD (R03DC014045