A motor theory of speech perception, initially proposed to account for results of early experiments with synthetic speech, is now extensively revised to accommodate recent findings, and to relate the assumptions of the theory to those that might be made about other perceptual modes. According to the revised theory, phonetic information is perceived in a biologically distinct system, a ‘module ’ specialized to detect the intended gestures of the speaker that are the basis for phonetic categories. Built into the structure of this module is the unique but lawful relationship between the gestures and the acoustic patterns in which they are variously overlapped. In consequence, the module causes perception of phonetic structure without translation from preliminary auditory impressions. Thus, it is comparable to such other modules as the one that enables an animal to localize sound. Peculiar to the phonetic module are the relation between perception and production it incorporates and the fact that it must compete with other modules for the same stimulus variations.

The central goal of this dissertation is to investigate the roles and interaction of articulatory, perceptual, and temporal elements in the phonological component of the grammar. This inquiry extends both to the input representations that are submitted to a phonological grammar, and to the constraints in the grammar. In order to adequately account for both production data and data from language typology, two elements must be integrated into the phonological component alongside articulatory gestures: perceptual features, which play an important role in determining phonotactic patterns, and gestural coordination, which establishes whether and how adjacent gestures are related to one another. This dissertation reports three experiments on the production of word-initial consonant clusters; such clusters are an appropriate environment for investigating how perception, articulation, and coordination interact in the phonology. The first experiment is an acoustic study of the production by native English speakers of Czech-possible consonant clusters (e.g. fkale, zbano, vnodi). Results show that speakers are more

Several studies on place perception of prevocalic stop consonants have shown that the apparent perceptual weight of release burst and formant transitions depends on the vowel context: bursts carry higher perceptual weight in high front vowel contexts like /i/ than in low non-front vowel contexts like /a/, while the reverse holds for formant transitions. This finding is generally interpreted as reflecting a context-dependent "reweighting" of burst and transition cues by the perceptual system. In this paper it is shown that the observed effect can be entirely accounted for by contextual variation of the distributions of the relevant cues themselves: Naturally produced stop bursts appear to be acoustically more distinctive in high front vowel contexts than in low non-front vowel contexts, while the reverse is true for formant transitions. The apparently context-dependent perceptual weight of burst and transitions can be reproduced with such cue distributions, even if the classification model itself contains fixed, context-independent linear boundaries. This claim is supported with acoustical and perceptual data of a burst-splicing experiment involving burst-spliced stop-vowel utterances containing the stops /p, t, k/ and vowels /a, i, y, u/.

In speech perception, children give particular patterns of weight to different acoustic cues (their cue weighting). These patterns appear to change with increased linguistic experience. Previous speech perception research has found a positive correlation between more analytical cue weighting strategies and the ability to consciously think about and manipulate segment-sized units (phonemic awareness). That research did not, however, aim to address whether the relation is in any way causal or, if so, then in which direction possible causality might move. Causality in this relation could move in 1 of 2 ways: Either phonemic awareness development could impact on cue weighting strategies or changes in cue weighting could allow for the later development of phonemic awareness. The aim of this study was to follow the development of these 2 processes longitudinally to determine which of the above 2 possibilities was more likely. Five-year-old children were tested 3 times in 7 months on their cue weighting strategies for a /so/–/So / contrast, in which the 2 cues manipulated were the frequency of fricative spectrum and the frequency of vowel-onset formant transitions. The

A set of three perceptual experiments is described. These experiments were designed to provide identification scores on CV sequences for French. Original stimuli were augmented with acoustic "monsters" where burst were excised or replaced. The first identification task shows that information carried by vocalic transitions can be overwritten by burst information. The importance of this phenomenon is inversely proportional to vowel aperture. The second experiment shows that these results are almost insensitive to relative amplitudes between the burst and the vowel. In the third experiment we manipulated the voice onset time (VOT) of the monsters using high quality analysis-resynthesis. Stimuli with a very short VOT were perceived as bilabials but VOT manipulation did not affect the /t/-/k/ confusions. These experiments claim for a dynamic model of stop identification where burst and vocalic transitions both contribute and compete to the phonetic decision. 1. INTRODUCTION The quest for ...

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This dissertation was produced which permit the inclusion as part of the dissertation the text of an original paper or papers submitted for publication. The dissertation must still conform to all other requirements explained in the “Guide for the Preparation of Master’s Theses and Doctoral Dissertations at The University of Texas at Dallas. ” It must include a comprehensive abstract, a full introduction and literature review and a final overall conclusion. Additional material (procedural and design data as well as descriptions of equipment) must be provided in sufficient detail to allow a clear and precise judgment to be made of the importance and originality of the research reported. It is acceptable for this dissertation to include as chapters authentic copies of papers already published, provided these meet type size, margin and legibility requirements. In such cases, connecting texts which provide logical bridges between different manuscripts are mandatory. Where the student is not the sole author of a manuscript, the student is required to make an explicit statement in the introductory material to that manuscript describing the student’s contribution to the work and