How auditory discontinuities and linguistic experience affect the perception of speech and non-speech in English- and Spanish-speaking listeners
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Speech perception results from a complex interplay between the operating characteristics of the auditory system (i.e., auditory discontinuities) and linguistic experience. Research in human infants and animals, and research using tone-onset-time (TOT) stimuli, a type of non-speech analogue of voice-onset-time (VOT) stimuli, has suggested that there is an underlying auditory basis for the perception of stop consonants based on a threshold for detecting temporal onset asynchronies in the vicinity of + 20 ms. Languages, however, differ in their reliance on temporal onset asynchrony-based auditory discontinuities in their [voice] categories. This dissertation sought to examine whether long-term linguistic experience with different [voice] categories (i.e., English or Spanish) affects the perception of non-speech stimuli that are analogous in their acoustic timing characteristics. This research was also designed to investigate the joint effects of linguistic experience and auditory mechanisms on phoneme structure and category learning. Three cross-linguistic studies were designed to look at (1) the production and perception of VOT and the perception of TOT, (2) the effects of stimulus range on the perception of VOT, and (3) the effects of auditory discontinuities on non-speech category learnability. Results indicate that linguistic experience does affect the perception of nonspeech stimuli, at least in certain circumstances. Thus, there is some commonality in the processes used to discriminate between non-speech sounds and those used to discriminate between speech sounds. Additionally, auditory discontinuities were found to influence both phoneme structure and category learning. It is suggested that English- and Spanishspeaking listeners use different cues to discriminate their [voice] categories. Results also suggest that there are perceptual asymmetries between the positive and the negative onset asynchrony-based auditory discontinuities. The relationships between auditory discontinuities, linguistic experience, discriminability, phoneme category structure, and learnability are discussed.