My research investigates systematic variation in the sound properties of speech and the perceptual and communicative consequences of such variation. I am particularly interested in ways in which that variation is constrained or conditioned by communicative or representational factors.

Some general areas of interest include:

• neighborhood-conditioned variation
• listener-directed and clear speech
• coarticulation, particularly nasal coarticulation
  
• perception of coarticulation, sub-phonemic detail
• visual prosody

(1) Previous work (mine and others') investigates the production of neighborhood-conditioned phonetic variation: we know that English speakers produce words from dense phonological neighborhoods with increased hyperarticulation and coarticulation. Currently, in work with Luciana Marques and Will Styler (CU PhD students), we are investigating neighborhood effects in French, looking at coarticulatory nasality as well as contrastive vowel nasality. We hope to extend our work to Brazilian Portuguese soon.

(2) We are also investigating the perception of this neighborhood-conditioned phonetic variation. I am interested in exploring whether the increased hyperarticulation and coarticulation in high neighborhood density words are perceptually beneficial (and potentially listener-directed), compensating for the inherent difficulty of high ND words. In work with Luciana Marques and Will Styler, we are currently looking at the role of degree of nasal coarticulation and hyperarticulation in the perception of high and low neighborhood density words.

(3) To support the perceptual work on nasality, I am working with Will Styler to identify and manipulate acoustic cues to nasality.

(4) With Georgia Zellou (UC Davis), Armik Mirzayan (USD), and David Rood (CU), I am working on description of contrastive and coarticulatory nasality in Lakota, a Siouan language spoken in the upper plains of the US. We are interested in how these two roles for nasality interact in shaping the patterns produced by native speakers.

(5) In work with Georgia Zellou, we are extending our study of listener-directed speech adjustments to a new category of listeners - infants - and to a new measure of lexical difficulty - age of acquisition. We are investigating the relationship between age of acquisition (or the age at which a child is reported to learn a given word) and neighborhood density (or the number of words phonological similar to a given word, which correlates with processing ease) in conditioning adjustments in hyperarticulation and coarticulation in infant-directed speech.