Exploring the information support for speech

Abstract

A well‐established feature of speech production is that talkers faced with both anticipated and unanticipated perturbations can spontaneously adjust the movement patterns of articulators such that the acoustic output remains relatively undistorted. Less clear is the nature of the underlying mechanism(s) involved. In this study we examined the production of static vowels and vowels embedded in a dynamic speech context in five subjects under normal conditions and a combined condition in which (a) the mandible was fixed via a biteblock, (b) proprioceptive information was reduced via bilateral anaesthetization of the temperomandibular joint, (c) tactile information from oral mucosa was reduced by extensive application of topical anaesthetic, and (d) auditory information was masked by white noise. Analysis of formant patterns revealed minimal distortion of the speech signal under the combined condition. These findings are unfavorable for a predictive simulation model which requires reliable peripheral information (Lindblom et al., 1979) and more in line with recent work suggesting that movement goals may be achieved by muscle collectives that behave qualitatively similar to a nonlinear vibratory system (Fowler et al., 1980; Kelso et al., 1980). [Work supported by NINCDS and BRSG.]