Compensation for Coarticulation: Implications for the Basis and Architecture of Speech Perception

Language users typically have the impression that understanding speech in their native tongue is instantaneous and effortless. This apparent ease belies a vastly complex chain of processes that must be engaged in order to derive meaning from the acoustic patterns of speech. Unlike computer speech recognition systems, human listeners adapt quickly to tremendous acoustic variability in the speech signal. This extremes of this variability can result, for instance, from unusual acoustic environments, new voices or accents, very fast speaking rates, and many other factors. Speech is one of the most difficult perceptual challenges that humans face, so research on its underlying mechanisms will not only further our understanding of human language, but may also help to unlock some of the deepest mysteries about the human mind. This basic knowledge may also serve to improve current speech technologies, and current methods of remediation for impairments in speech comprehension and production.

With the support of the National Science Foundation, Dr. Magnuson is studying a speech perception phenomenon called 'compensation for coarticulation' with the goal of refining current theories of speech perception. Compensation for coarticulation is a phenomenon whereby the perception of a sound is affected by the qualities of preceding or following sounds. Traditional explanations of this phenomenon appeal to active mechanisms of perceptual adjustment based on physical properties of the vocal tract and speech articulators. However, there are now three distinct explanations that account for overlapping subsets of results, each of which follows from a different theory of speech perception. Dr. Magnuson and his research team will use acoustic analyses and speech experiments with human speakers and listeners in order to distinguish between these differing explanations of compensation for coarticulation. The results of this project promise to advance our general understanding of the perceptual mechanisms that underlie speech and potentially many sensory experiences.