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.

Mapping from acoustic signals to lexical representations is a complex process mediated by a number of different levels of representation. This paper reviews properties of the phonetic and phonological levels, and hypotheses about how category structure is represented at each of these levels, and evaluates these in light of relevant electrophysiological studies of phonetics and phonology. The paper examines evidence for two alternative views of how infant phonetic representations develop into adult representations, a structure-changing view and a structure-adding view, and suggests that each may be better suited to different kinds of phonetic categories. Electrophysiological results are beginning to provide information about phonological representations, but less is known about how the more abstract representations at this level could be coded in the brain.

Recently, speech researchers have begun to examine the formation of speech sound (phonetic) categories and to analyze the internal structure of the consequent categories. One of the most prominent products of this subfield has been the Perceptual Magnet Effect (PME) and the attendant Native Language Magnet (NLM) theory of Kuhl (1991, 2000). In the present paper, a critical review of the evidence for NLM is offered. Because of concerns about the nature of the stimuli, possible confounds inherent in the empirical procedures and failed replications, it is concluded that there is little positive evidence supporting NLM. However, the goal of uncovering the structures of phonetic categories and mechanisms responsible for those structures remains central to an understanding of language acquisition and speech perception more generally. Data from several empirical paradigms investigating the formation and structure of complex auditory categories are beginning to form a coherent picture of phonetic category acquisition.

Purpose: This paper examined whether naïve listeners could perceive phonetic detail in children's productions of /s / and /T/, and whether their perception of /s / and /θ / could be biased by their belief about the child's overall speech-production ability. Method: In Experiment 1, listeners provided judgments of children's productions of /s / and /T/ using a visual analog scale (VAS). In Experiment 2, different listeners provided 'correct ' and 'incorrect ' judgments of the same tokens in a task in which they were led to believe that some children were older and had more-accurate speech, and others were younger and had lessaccurate speech. For Experiment 1, linear regression modeling was used to determine the relationship between VAS responses and psychoacoustic characteristics of the stimuli. For Experiment 2, within-subjects comparisons of accuracy judgments for the two conditions were conducted. Results: In Experiment 1, VAS judgments showed that listeners were able to perceive fine phonetic detail in children's productions, including differences between correct productions and clear substitutions. In Experiment 2, listener bias was found to have a small influence on listener

Speech perception (SP) most commonly refers to the perceptual mapping from the highly variable acoustic speech signal to a linguistic representation, whether it be phonemes, diphones, syllables, or words. This is an example of categorization, in that potentially discriminable speech sounds are assigned to functionally equivalent classes. In this tutorial, we present some of the main challenges to our understanding of the categorization of speech sounds and the conceptualization of SP that has resulted from these challenges. We focus here on issues and experiments that define open research questions relevant to phoneme categorization, arguing that SP is best understood as perceptual categorization, a position that places SP in direct contact with research from other areas of perception and cognition.

This dissertation investigates the phenomenon of language-specificity in the auditory perception of Chinese tones. Chinese and American English (AE) listeners participated in a series of perception experiments, which involved short ISIs (300ms in Experiment 1 and 100ms elsewhere) and an AX discrimination (limited set in Experiments 2 and 3, speeded response in Experiments BJ, RG and YT) or AX degreeof-difference rating (Experiment 4) task. All experiments used natural speech monosyllabic tone stimuli, except Experiment 2, which used sinewave simulations of Putonghua (Beijing Mandarin) tones. AE listeners showed psychoacoustic listening in all experiments, paying much attention to onset and offset pitch. Chinese listeners showed language-specific patterns in all experiments to various degrees. The most robust language-specific effects of Putonghua were found in Experiments 1, 3 and 4, where the T214 (as well as T35) neutralization rule shortened the perceptual distance between T35 and T214 (or that between T55 and T35) for Chinese listeners. Cross-dialectal as well as age differences were observed among Chinese listeners in Experiments BJ, RG and YT

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