Research in Phonology and Phonetics

My interests lie in experimental and theoretical research that investigates the physiological and cognitive bases of phonological systems. My current research projects are listed below.

Speech prosody

I have several current projects that investigate the production and perception of prosody in English and other languages. A major focus of this work is on prosody in spontaneous, conversational speech and methods for prosody annotation. For more information about these projects and links to downloadable papers and presentations, please visit my lab website at the Linguistic Laboratory for Speech Prosody.

The phonetics and phonology of Vowels: Harmony, Coarticulation, and Vowel Shift

Vowel harmony is a kind of phonotactic dependency in which the vowels in a phonological domain must agree in some or all of their features. My research examines vowel harmony in speech production and perception. The production studies use a speeded repetition experimental paradigm to compare the accuracy and/or speed of harmonic and disharmonic vowel sequences in the production of nonsense words [Publications 17, Slides S3, S5]. Acoustic studies examine the nature of coarticulation in harmonic and disharmonic sequences for the dimensions of vowel height (F1) and backness (F2) [Publications 18, S5]. Perception studies look at the accuracy of consonant and vowel identification as a function of vowel harmony in VCV sequences [Publications 14, S2].

Collaborative work with Bob McMurray (U Iowa) introduces statistical models of the parsing mechanism in speech perception that allows listeners to cope with variability due to coarticulation and other factors, and to use that variability to predict upcoming phonological context [Publications 18, 23, S7]. The role of abstract feature structures and rules operating on them in the analysis of harmony are addressed in [Publications 10, 17].

Vowel shift describes a diachronic sound change in which some or all vowels in a system shift their place of articulation in the vowel space. Work with José I. Hualde, Yoonsook Mo and Heejin Kim compares the effects of prosodic prominence in two American English speech corpora to known patterns of vowel shift and finds a partial similarity between the two phenomena [Publication S10]. Work with Michael Blasingame and José I. Hualde examines the interaction between prosodic prominence and vowel shift for a set of recently completed and ongoing shifts in Chicago (American) English, and finds that these effects can go in opposite directions, suggesting independent mechanisms at work [Publication 19].

Phonotactic learning

This project investigated implicit learning of phonotactic dependencies based on brief exposure, with adult subjects, and was part of my collaborative research with Gary Dell and Cynthia Fisher. A production study using speeded repetition tasks showed that subjects can learn ranking relations among novel violable constraints [Publication 13]. Further studies with Hahn Koo investigated the role of similarity and perceptual distance in the implicit learning of phonotactic dependencies that encode assimilation and dissimilation between consonants or vowels [Publications 15, 16, S6]. Projects with graduate students Karen Lichtman and Erin Rusaw test implicit learning of phonotactic constraints dependent on speaker voice [Publication S11], and on learning of constraints in the experimental language that violate the subject's native language phonotactics [Publication S9].

Prosody variation in American English dialects: AAVE

In collaboration with Erik Thomas (N Carolina State U) and graduate student Erica Britt, I examined the intonational characteristics of African-American Vernacular English in comparison with European-American English for speakers from North Carolina. [Publications S4]

Issues in phonological theory

Findings from experimental, computational and statistical research in phonology have implications for phonological theory. In several papers I revisit key concepts in phonological theory such as the phonological cycle [Publications 1, 2, 3] underlying representations [Publications 9, 22], feature structures [Publications 4, 5, 6, 8, 17], syllable structure [Publication 24, S12] and grammaticization [Publications 11, S2], and discuss the benefits of phonological research based on large speech corpora [Publication 26].

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