This project is intended to provide new information about the control processes that mediate the production and perception of adult speech. Emphasis will be placed on the study of syntactic influences on segmental timing in speech production and the way in which the perception of timing may play a role in recovering syntactic information. The study of speech production involves a sentence-reading paradigm in which key words are inserted in phonetically matched sentences. During the current grant period, we intend to extend our work in this area. Specific projects include (a) a study of timing effects for speech segments belonging to different grammatical categories (e.g., adjective, noun, adverb), (b) a study of hierarchical branching effects on speech timing, (c) tests of competing theories of syntactic boundary strengths in blocking phonological rules that normally operate across word boundaries, and (d) tests of fundamental frequency resetting at clause-and phrase-boundaries, as well as fundamental frequency effects at sites of syntactic transformations. We will also begin studies to test whether listeners can detect and utilize the information provided by the speaker to decode structural information during on-line sentence perception. Finally, theoretical work will continue toward the development of a model of syntactic-to-phonetic coding in speech production. The theory is designed to specify (a) the types of grammatical domains that may influence phonetic coding, (b) ordered application of grammatical influences by successively narrow domains, incorporating left-to-right as well as hierarchial constraints, and (c) the form of the speakers grammatical representation at selected domains in cases involving linguistic controversy. Application to speech synthesis-by-rule will be undertaken upon the completion of the above projects.