The experiments proposed in this project focus on the nature of articulatory overlap between vowel and consonant gestures, and the interactions among a variety of levels of articulatory organization. These experiments will further the long-term objective of understanding the spatiotemporal organization of speech production, an essential prerequisite to understanding how the production mechanism malfunctions in speech disorders. In general, the techniques employed in the proposed studies will provide parallel observations of the speech acoustic signal, articulatory movements, and physiological measures such as electromyographic and aerodynamic activity. The primary hypothesis underlying the proposed studies is that a major component of phonetic structure resides in the organization of articulation into discrete, spatiotemporally overlapping articulatory gestures. In a first group of studies, we propose to investigate one of the most important areas of gestural overlap, that of vowels and consonants, to determine the nature of constraints on vowel-consonant overlap. In a second group of studies, we propose to explore how higher levels of articulatory phonetic structure, e.g., syllable and utterance level structure, affect the overlap among gestures, as well as the nature of the individual gestures. A second hypothesis being pursued in this project is that a dynamical systems approach to characterizing articulatory coordination may lead to a more explanatory statement of such coordination. This hypothesis underlies a number of the proposed experiments, and is a central aspect of the computational model of articulatory organization currently being developed. The model will be used throughout the proposed research to test the results of experimental analyses.
