Brief Report: Atypical Temporal Sensitivity in Coarticulation in Autism: Evidence from Sibilant-Vowel Interaction in Cantonese.

PURPOSE: Atypicalities in the prosodic aspects of speech are commonly considered in clinical assessments of autism. While there is an increasing number of studies using objective measures to assess prosodic deficits, such studies have primarily focused on the intonational and rhythmic aspects of prosody. Little is known about prosodic deficits that are reflected at the segmental level, despite the strong connection between prosody and segmental realization. This study examines the nature of sibilant-vowel coarticulation among male adult native speakers of Cantonese with autism and those without. METHODS: Fifteen Cantonese-speaking autistic (ASD) adults (mean age = 25 years) and 23 neuro-typical (NT) adults (mean age = 20 years) participated. Each participant read aloud 42 syllables with a sibilant onset in carrier phrase. Spectral means and variance, skewness and kurtosis were measured, and regressed by vocalic rounding (rounded vs. unrounded), cohort (ASD vs. NT), sibilant duration, and articulation rate. RESULTS: While neurotypical participants exhibit sibilant-vowel coarticulation that are sensitive to variation in sibilant duration, autistic participants show no sensitivity to segmental temporal changes. CONCLUSION: These findings point to the potential for atypicalities in prosody-segment interaction as an important characteristic of autistic speech.

Individual variability in subcortical neural encoding shapes phonetic cue weighting.

Recent studies have revealed great individual variability in cue weighting, and such variation is shown to be systematic across individuals and linked to differences in some general cognitive mechanism. The present study investigated the role of subcortical encoding as a source of individual variability in cue weighting by focusing on English listeners' frequency following responses to the tense/lax English vowel contrast varying in spectral and durational cues. Listeners differed in early auditory encoding with some encoding the spectral cue more veridically than the durational one, while others exhibited the reverse pattern. These differences in cue encoding further correlate with behavioral variability in cue weighting, suggesting that specificity in cue encoding across individuals modulates how cues are weighted in downstream processes.

Tonal context influences tone-duration interaction: Evidence from Cantonese.

Phonetic typological studies suggest that syllable duration is inversely correlated with the accompanying tone's approximate average f0, and tones with dynamic f0 movement tend to be in longer syllables rather than shorter ones. Systematic instrumental investigations on tone-duration interaction remain scant, however; existing studies might be confounded as tonal context may impact duration realization due to phonetic constraints on tonal movement. This study investigates the effect of tonal environment on the durational realization of tones in Cantonese, showing that tone-dependent duration variation is governed by the tonal context. Implications of these findings for existing phonetic typology concerning tone-duration interaction are discussed.

Perceptual Cue Weighting Is Influenced by the Listener's Gender and Subjective Evaluations of the Speaker: The Case of English Stop Voicing.

Speech categories are defined by multiple acoustic dimensions and their boundaries are generally fuzzy and ambiguous in part because listeners often give differential weighting to these cue dimensions during phonetic categorization. This study explored how a listener's perception of a speaker's socio-indexical and personality characteristics influences the listener's perceptual cue weighting. In a matched-guise study, three groups of listeners classified a series of gender-neutral /b/-/p/ continua that vary in VOT and F0 at the onset of the following vowel. Listeners were assigned to one of three prompt conditions (i.e., a visually male talker, a visually female talker, or audio-only) and rated the talker in terms of vocal (and facial, in the visual prompt conditions) gender prototypicality, attractiveness, friendliness, confidence, trustworthiness, and gayness. Male listeners and listeners who saw a male face showed less reliance on VOT compared to listeners in the other conditions. Listeners' visual evaluation of the talker also affected their weighting of VOT and onset F0 cues, although the effects of facial impressions differ depending on the gender of the listener. The results demonstrate that individual differences in perceptual cue weighting are modulated by the listener's gender and his/her subjective evaluation of the talker. These findings lend support for exemplar-based models of speech perception and production where socio-indexical features are encoded as a part of the episodic traces in the listeners' mental lexicon. This study also shed light on the relationship between individual variation in cue weighting and community-level sound change by demonstrating that VOT and onset F0 co-variation in North American English has acquired a certain degree of socio-indexical significance.

A New System of Cantonese Tones? Tone Perception and Production in Hong Kong South Asian Cantonese.

Studies in language contact have identified many instances of linguistic variation and grammatical innovations introduced by speakers from multi-ethnic urban neighborhoods. This study focuses on the variety of Cantonese spoken by South Asian youths in Hong Kong, specifically their production and perception of Hong Kong Cantonese tones. Our findings show that the South Asian Cantonese speakers have a smaller tonal inventory than the canonical six-tone system of standard Hong Kong Cantonese and their tonal discrimination abilities are also more impoverished relative to their ethnic Chinese peers. Further analysis shows a positive correlation between tonal discrimination accuracy and tonal realization distinctness among the South Asian speakers, but not among the ethnic Chinese. These findings suggest that South Asian Cantonese speakers might have developed a distinct tone system from their ethnic Chinese peers.

Individual Differences in Categorization Gradience As Predicted by Online Processing of Phonetic Cues During Spoken Word Recognition: Evidence From Eye Movements.

Recent studies have documented substantial variability among typical listeners in how gradiently they categorize speech sounds, and this variability in categorization gradience may link to how listeners weight different cues in the incoming signal. The present study tested the relationship between categorization gradience and cue weighting across two sets of English contrasts, each varying orthogonally in two acoustic dimensions. Participants performed a four-alternative forced-choice identification task in a visual world paradigm while their eye movements were monitored. We found that (a) greater categorization gradience derived from behavioral identification responses corresponds to larger secondary cue weights derived from eye movements; (b) the relationship between categorization gradience and secondary cue weighting is observed across cues and contrasts, suggesting that categorization gradience may be a consistent within-individual property in speech perception; and (c) listeners who showed greater categorization gradience tend to adopt a buffered processing strategy, especially when cues arrive asynchronously in time.

Temporal Coordination and Prosodic Structure in Autism Spectrum Disorder: Timing Across Speech and Non-speech Motor Domains.

Individuals with autism spectrum disorder (ASD) often exhibit disordered speech prosody, but sources of disordered prosody remain poorly understood. We explored patterns of temporal alignment and prosodic grouping in a speech-based metronome repetition task as well as manual coordination in a drum tapping task among Cantonese speakers with ASD and normal nonverbal IQ and matched controls. Results indicate similar group results for prosodic grouping patterns, but significant differences in relative timing and longer syllable durations at phrase ends for the ASD group. Variability on the speech task was significantly correlated with variability on the drumming task, consistent with the view that impairment in both speech and non-speech motor domains can be linked with deficits in temporal processing.

Perceived Masculinity Predicts U.S. Supreme Court Outcomes.

Previous studies suggest a significant role of language in the court room, yet none has identified a definitive correlation between vocal characteristics and court outcomes. This paper demonstrates that voice-based snap judgments based solely on the introductory sentence of lawyers arguing in front of the Supreme Court of the United States predict outcomes in the Court. In this study, participants rated the opening statement of male advocates arguing before the Supreme Court between 1998 and 2012 in terms of masculinity, attractiveness, confidence, intelligence, trustworthiness, and aggressiveness. We found significant correlation between vocal characteristics and court outcomes and the correlation is specific to perceived masculinity even when judgment of masculinity is based only on less than three seconds of exposure to a lawyer's speech sample. Specifically, male advocates are more likely to win when they are perceived as less masculine. No other personality dimension predicts court outcomes. While this study does not aim to establish any causal connections, our findings suggest that vocal characteristics may be relevant in even as solemn a setting as the Supreme Court of the United States.

Vowel-dependent variation in Cantonese /s/ from an individual-difference perspective.

Individual variation is ubiquitous in the acoustic realization of human speech; however, little is known about the nature of individual differences in coarticulation. Through an in-depth case study of the temporal dynamics of vocalic influences on the acoustic realization of Cantonese /s/, this study demonstrates that coarticulatory effects may vary by the sex and self-reported autistic-like traits of the individual. These findings have significant implications for research in phonetics, phonology, and sound change.

The stability of perceptual compensation for coarticulation within and across individuals: a cross-validation study.

Perceptual compensation for coarticulation (PCCA) refers to listener responses consistent with perceptual reduction of the acoustic effects of the coarticulatory context on a target sound. The robustness of PCCA across individuals and across tasks have not been studied together previously. This study reports the results of two experiments designed to determine the robustness of perceptual compensation for vocalic influence on sibilant perception across tasks and the stability of such compensatory response within an individual. Identification and discrimination data, collected in the laboratory and on Amazon's Mechanical Turk, showed that individuals are moderately stable in their PCCA responses across tasks and the level of stability is consistent across both the lab-based and the internet-based cohorts, although some differences are observed.

Phonetic imitation from an individual-difference perspective: subjective attitude, personality and "autistic" traits.

Numerous studies have documented the phenomenon of phonetic imitation: the process by which the production patterns of an individual become more similar on some phonetic or acoustic dimension to those of her interlocutor. Though social factors have been suggested as a motivator for imitation, few studies has established a tight connection between language-external factors and a speaker's likelihood to imitate. The present study investigated the phenomenon of phonetic imitation using a within-subject design embedded in an individual-differences framework. Participants were administered a phonetic imitation task, which included two speech production tasks separated by a perceptual learning task, and a battery of measures assessing traits associated with Autism-Spectrum Condition, working memory, and personality. To examine the effects of subjective attitude on phonetic imitation, participants were randomly assigned to four experimental conditions, where the perceived sexual orientation of the narrator (homosexual vs. heterosexual) and the outcome (positive vs. negative) of the story depicted in the exposure materials differed. The extent of phonetic imitation by an individual is significantly modulated by the story outcome, as well as by the participant's subjective attitude toward the model talker, the participant's personality trait of openness and the autistic-like trait associated with attention switching.

Perceptual compensation is correlated with individuals' "autistic" traits: implications for models of sound change.

Variation is a ubiquitous feature of speech. Listeners must take into account context-induced variation to recover the interlocutor's intended message. When listeners fail to normalize for context-induced variation properly, deviant percepts become seeds for new perceptual and production norms. In question is how deviant percepts accumulate in a systematic fashion to give rise to sound change (i.e., new pronunciation norms) within a given speech community. The present study investigated subjects' classification of /s/ and // before /a/ or /u/ spoken by a male or a female voice. Building on modern cognitive theories of autism-spectrum condition, which see variation in autism-spectrum condition in terms of individual differences in cognitive processing style, we established a significant correlation between individuals' normalization for phonetic context (i.e., whether the following vowel is /a/ or /u/) and talker voice variation (i.e., whether the talker is male or female) in speech and their "autistic" traits, as measured by the Autism Spectrum Quotient (AQ). In particular, our mixed-effect logistic regression models show that women with low AQ (i.e., the least "autistic") do not normalize for phonetic coarticulation as much as men and high AQ women. This study provides first direct evidence that variability in human's ability to compensate for context-induced variations in speech perceptually is governed by the individual's sex and cognitive processing style. These findings lend support to the hypothesis that the systematic infusion of new linguistic variants (i.e., the deviant percepts) originate from a sub-segment of the speech community that consistently under-compensates for contextual variation in speech.