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

Acoustic correlates of prosody

This project involves acoustic studies of the correlates of phrasal stress ('accent') and prosodic phrasing in suprasegmental features of pitch, duration, loudness and voice quality. This project also examines prosody-conditioned variation at the segmental level, through investigations of the effects of prosodic prominence (stress, accent) and prosodic phrase boundaries on the acoustic cues to phonological contrasts for consonants and vowels. These studies are based on corpora of broadcast and spontaneous conversational speech. This work is carried out by members of the Linguistic Laboratory for Speech Prosody. Click here for papers from this project.

Prosody and disfluency modeling for automatic speech recognition

This collaborative project with Mark Hasegawa-Johnson and Chilin Shih is investigating approaches to ASR that adopt an explicit model of the prosodic and disfluency structures in natural speech, using data from corpora of broadcast news and telephone conversation speech.Click here for papers from this project.

The phonetic bases of vowel harmony

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. This project 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. Acoustic studies currently underway examine the nature of coarticulation in harmonic and disharmonic sequences for the dimensions of vowel height (F1) and backness (F2). Perception studies look at the accuracy of consonant and vowel identification as a function of vowel harmony in VCV sequences. A new collaborative study with Bob McMurray (U Iowa) is investigating the timecourse of perception in vowel harmony structures using eye-tracking in a Visual World experimental paradigm (stay tuned!). Click here for papers and presentations from this project.

Phonotactic learning

This project looks at evidence for implicit learning of phonotactic dependencies based on brief exposure, with adult subjects, and is part of my collaborative research with Gary Dell and Cynthia Fisher. Production studies with graduate student Hahn Koo (UIUC Linguistics) investigate the role of similarity and perceptual distance in the implicit learning of phonotactic dependencies that encode assimilation and dissimilation between consonants or vowels. Click here for papers and presentations from this project.

Prosody variation in American English dialects: AAVE

In collaboration with Erik Thomas, I am investigating the intonational characteristics of African-American Vernacular English in comparison with European-American English for speakers from North Carolina. Click here for papers and presentations from this project.