The Relative Effects of Phonetic and Phonological Salience in Speech Sound Processing

Abstract

This dissertation examines the relative effects of phonetic salience and phonological prominence on speech sound processing. Three test cases, respectively, investigate the processing of consonants versus vowels by speakers of German, Hebrew, and Amharic; the processing of aspirated versus unaspirated stops by speaker of Spanish and Thai; and the perception of high versus low tones by speakers of French and Tlicho (Dene; Canada). One of the types of sounds examined in each test case is said to be more phonetically salient based on its acoustic properties, and the other is more prominent in the phonological grammar of one of the groups of speakers examined. The test cases are each comprised of an immediate serial recall (ISR) experiment and an artificial language learning (ALL) experiment.

Results show that phonetics and phonology are processed differently, supporting the notion that the two represent separate modules in the grammar. Specifically, phonetic effects are more likely to emerge in the ISR tasks, which involve short-term processing, whereas phonological effects tended to emerge in tasks that required longer-term memory and the association of auditory stimuli with lexical meaning. The consistency of phonetic effects in the ISR experiments lends support to the notion of universal acoustic salience, such that a given sound can be easier to process than another sound based solely on their respective acoustic properties. The phonological effects that emerge in a subset of the results show that this effect of acoustic salience can be outweighed by language-specific grammatical prominence effects, but only when the task being performed requires a relatively deeper level of processing. Taken together, these results bolster our understanding of acoustic salience and its universality, and show that a given sound's role in the phonological patterning in a language can impact the ways in which is processed by speakers of this language.