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The Role of Acoustic Detail in the Production and Processing of Vowels in Spontaneous Speech
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- Author / Creator
- Sims, Michelle Nicole
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This dissertation examines the correlations between morphology and spontaneous speech production and perception. Specifically, this dissertation focuses on a subset of irregular English verbs and the production of vowel formants and the perception of vowel durations of those verbs. The dissertation is composed of three studies. Study 1 examines the patterns of formant movement in monosyllabic verbs. Both qualitative and quantitative analyses in Study 1 show that the spontaneously produced formant movement patterns are similar to the patterns found in more carefully controlled citation speech. The formant data gathered in Study 1 was then used in Study 2 to investigate the effect that morphology has on the production of vowels. Morphology was measured by determining whether a vowel appeared in the past or present tense, and by calculating the morphological support for a particular vowel through Naive Discriminant Learning metrics. It was predicted that vowels in the morphologically uncertain tense (past) and/or with a high level of morphological support would be produced with acoustic enhancement. To test these predictions, analyses of four related measures of acoustic detail were conducted: 1) F1 and F2 linear dispersion from vowel space centre; 2) F1 and F2 linear deviation from vowel onset; 3) F1 and F2 linear deviation from vowel offset; and 4) non-linear amount of F1 and F2 movement. Each measure was analyzed with all of the vowels pooled together (global analysis), and then vowel-by-vowel (fractionated analysis). The four main findings of Study 2 are: 1) the global analyses support the predictions; 2) this pattern is not uniform across all vowels in the vowel-by-vowel analyses; 3) the vowel-by-vowel analyses better model the formant data than the global analyses; and 4) the linear analyses also better model the formant data than the non-linear analyses. Study 2 discusses the need for granular models of morphological predictability that account for vowel-specific conditions, since global generalizations made about the relationship between morphology and formant production were not found to be uniform for every vowel. Study 3 builds upon Study 2 by testing whether acoustic details in speech are produced in a way that necessarily facilitates perception. Previous research in production has found there to be a correlation between the morphological support for an irregular verb and the duration of its vowel. In both lexical and morphological decision experiments, Study 3 tested whether this production-related correlation affects perception. To test this, the relationship between morphological support and vowel duration was reversed. It was predicted that production and processing are linked, thus disrupting this production-based relationship would lead to processing difficulty in the lexical and morphological decision tasks. Study 3 finds that processing indeed becomes more difficult, but only in certain tasks and under certain conditions. This indicates that there is a link between production and processing, though the link is weaker than predicted. As with Study 2, Study 3 discusses the implications of a global generalization that does not uniformly hold across all conditions. Taken together, the results of the three studies are discussed in terms of an understanding of the mental representation of acoustic detail, and how acoustic detail can weakly link production and perception.
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- Graduation date
- Fall 2016
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- Type of Item
- Thesis
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- Degree
- Doctor of Philosophy
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- License
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.