My research investigates the "dance of the tongue, lips, and jaw"--the motions of the speech articulators. Speech movements are quick yet fluid, overlapping yet coordinated, they are often quasi-rhythmic, and they provide a basis for the emergence of linguistic systems. By observing the spatial and temporal effects of perturbations of speech motor planning, we can gain insight into how linguistic systems are represented cognitively. One of my main interests is in how articulatory, rhythmic, and prosodic systems interact--these interactions constrain and inform our theories of the prosodic hierarchy. I am also interested in the interplay between motor and sensory representations in working and long-term memory, as well as their respective contributions to sound change. My theoretical approach is based upon dynamical modeling of interactions between articulatory and prosodic systems during the planning and production of speech.