| Summary: | Thesis (Ph. D.)--Harvard-MIT Division of Health Sciences and Technology, 2006. === This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. === Includes bibliographical references (p. 145-147). === Nasal codas in English and Standard Chinese (SC) are compared to distinguish between the acoustic correlates of language-universal distinctive features and language-specific enhancing attributes. The distinctive feature theory and the theory of enhancement provide a framework for quantifying the acoustic and articulatory patterns observed in the two languages. An acoustic model of nasalization is first presented, in which the area of the velopharyngeal port and the place of oral constriction are varied, in order to observe the behavior of the acoustic correlates for the feature [nasal] and to establish a quantal relation between the continuous displacement of the primary articulator and the acoustic consequence of this displacement. The first two experiments identify differences in the distribution of acoustic correlates of nasalization contained in the vowel transition and the murmur regions in vowel-nasal environments in English and SC. Results for the low vowel /a/ show a mapping based on vowel rather than coda similarity. Acoustic analysis shows that the SC vowel /a/ shifts in the frequency of the second formant (F2) depending on the nasal coda, while the English vowel does not. === (cont.) The SC mid vowel /e/ shifts in F2 while the SC high vowel /i/ does not. Furthermore, analysis of syllable-initial nasals in Chinese and English shows that the SC nasals behave like the English nasals. The third experiment is a perceptual study in which subjects are asked to make judgments of the place of articulation based on limited portions of stimuli that can be either nasal or non-nasal and contain one of the three vowels. The nasal place of articulation was identified best when the nasal was preceded by the mid vowel /e/, was identified less when followed by the low vowel /a/, and was identified the worst when the nasal was preceded by the high vowel /i/. Together, the results of these experiments suggest that language-specific constraints play an important role in determining the enhancing attributes that occur alongside languageuniversal features. The interactions of the distinctive features and the enhancing gestures may lead to differences in the acoustic manifestation of the same feature in different languages. === by Xiaomin Mou. === Ph.D.
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