The overall aim of our research is to use the demonstrated tendency for adults to imitate the speech they hear as a tool to explore the nature of speech perception.  In initial studies, we explore the nature of objects of speech perception (i.e., acoustic or articulatory), a topic that is much debated in the field of speech research.  The question is of interest in its own right as an important topic for basic research.  It also has implications for application, for example, for the design of successful speech recognition devices.  We intend to confirm and then exploit the tendency that humans appear to have to imitate the speech of others.  We also propose to explore what is imitated when imitations occur.  If our initial findings suggest that perceptual objects are acoustic or auditory, then we will ask whether imitations are of surface acoustic forms or of more abstract normalized forms.  If initial findings suggest articulatory perceptual objects, then we will ask whether surface articulations or linguistic gestures are imitated.  We also propose to explore the kinds of factors (especially varieties of language learning) that influence both imitation facility and fidelity.  An important research tool for our project is the electromagnetic articulometer (EMMA) that will allow us to track the gestures of our subjects and relate them to those of the speech that they shadow.  However, other techniques involving acoustic measurement, perceptual judgments or both will also be used to assess imitative fidelity.  We expect our research to contribute usefully to the debate about perceptual objects, and, therefore to advances in both basic and applied research.