Using probability distributions to account for recognition of canonical and reduced word forms

The frequency of a word form influences how efficiently it is processed, but canonical forms often show an advantage over reduced forms even when the reduced form is more frequent. This paper addresses this paradox by considering a model in which representations of lexical items consist of a distribution over forms. Optimal inference given these distributions accounts for item based differences in recognition of phonological variants and canonical form advantage

The time course of auditory and language-specific mechanisms in compensation for sibilant assimilation

Models of spoken-word recognition differ on whether compensation for assimilation is language-specific or depends on general auditory processing. English and French participants were taught words that began or ended with the sibilants /s/ and /∫/. Both languages exhibit some assimilation in sibilant sequences (e.g., /s/ becomes like [∫] in dress shop and classe chargée), but they differ in the strength and predominance of anticipatory versus carryover assimilation. After training, participants were presented with novel words embedded in sentences, some of which contained an assimilatory context either preceding or following. A continuum of target sounds ranging from [s] to [∫] was spliced into the novel words, representing a range of possible assimilation strengths. Listeners' perceptions were examined using a visual-world eyetracking paradigm in which the listener clicked on pictures matching the novel words. We found two distinct language-general context effects: a contrastive effect when the assimilating context preceded the target, and flattening of the sibilant categorization function (increased ambiguity) when the assimilating context followed. Furthermore, we found that English but not French listeners were able to resolve the ambiguity created by the following assimilatory context, consistent with their greater experience with assimilation in this context. The combination of these mechanisms allows listeners to deal flexibly with variability in speech forms

Individual talker and token covariation in production of multiple cues to stop voicing

Background/Aims: Previous research found that individual talkers have consistent differences in the production of segments impacting the perception of their speech by others. Speakers also produce multiple acoustic-phonetic cues to phonological contrasts. Less is known about how multiple cues covary within a phonetic category and across talkers. We examined differences in individual talkers across cues and whether token-by-token variability is a result of intrinsic factors or speaking style by examining within-category correlations. Methods: We examined correlations for 3 cues (voice onset time, VOT, talker-relative onset fundamental frequency, f0, and talker-relative following vowel duration) to word-initial labial stop voicing in English. Results: VOT for /b/ and /p/ productions and onset f0 for /b/ productions varied significantly by talker. Token-by-token within-category variation was largely limited to speaking rate effects. VOT and f0 were negatively correlated within category for /b/ productions after controlling for speaking rate and talker mean f0, but in the opposite direction expected for an intrinsic effect

Individual differences in the link between perception and production and the mechanisms of phonetic imitation.

This study investigates the relationship between speech perception and production using explicit phonetic imitation. We used manipulated natural vowel (head-had) stimuli varying in spectral quality and duration in both perception and production tasks to explore the perception-production link in a direct and controlled way. We examined (1) whether individual listeners’ perceptual cue weights are related to their patterns of phonetic imitation and (2) phonological and perceptual constraints underlying phonetic imitation. Results showed that better perceptual abilities (i.e. larger cue weights) were related to better imitation of vowel duration. Furthermore, imitation of vowel spectral quality was mediated by contrast maintenance while vowel duration was not. Overall, vowel duration was better imitated despite being the less important cue perceptually. These results suggest that speech perception and production are indeed linked at the individual level, and both linguistic and perceptual-cognitive factors play a role in this process

Phonetic detail is used to predict a word’s morphological composition

An eye-tracking experiment tested the hypothesis that listeners use within-word fine phonetic detail that systematically reflects morphological structure, when the phonemes are identical (dis in discolour (true prefix) vs. discover (pseudo prefix)) and when they differ (re-cover vs. recover). Spoken sentence pairs, identical up to at least the critical word (e.g. I’d be surprised if the boys discolour/discover it), were crossspliced at the prefix-stem boundary to produce stimuli in which the critical syllable’s acoustics either matched or mismatched the sentence continuation. On each trial listeners heard one sentence, and selected one of two photographs depicting the pair. Matched and mismatched stimuli were heard in separate sessions, at least a week apart. Matched stimuli led to more looks to the target photograph overall and timecourse analysis suggested this was true at the earliest moments. We also observed stronger effects for earlier trials and the effects tended to weaken over the course of the experiment. These results suggest that normal speech perception involves continuously monitoring phonetic detail, and, when it is systematically associated with meaning, using it to facilitate rapid understanding.Marie Curie Research Training Network 1157 Sound to Sense, MRTN-CT-2006-03556

Individual and dialect differences in perceiving multiple cues: A tonal register contrast in two Chinese Wu dialects

This study investigates how multiple cues contribute to multi-dimensional phonological contrasts at both the group level and the individual level, and how dialectal experience shapes listeners’ perceptual strategies. We examine a tonal register contrast in two Chinese Wu dialects signaled by three cues: pitch height, voice quality, and pitch contour. We found that 1) at the group level, cue weights are context-specific, i.e., vary by tone, and some contrasts rely more heavily on multiple cues than others; 2) dialectal experience affects listeners’ perceptual strategy: Shanghai listeners, with their own dialect having a smaller voice quality distinction, do not rely more on the cue even when listening to stimuli with a clear breathy-modal distinction, comparing to Jiashan listeners; 3) individuals’ cue weights are correlated in a positive manner, meaning that some listeners show overall larger cue weights than others; larger variability is found when the contrast has more than one salient cue, in which case individuals have different options of choosing one cue over another as the primary cue and this can work against the positive correlation