Compensation to articulatory perturbation: Perceptual data

The perceptual adequacy of vowels, stop consonants, and fricatives produced under conditions of articulatory perturbation was explored. In a previous study [McFarland and Baum, J. Acoust. Sec. Am. 97, 1865-1873 (1995)], acoustic analyses of segments produced in two subtests (immediate compensation and postconversation) revealed small but significant changes in spectral characteristics of vowels and consonants under bite-block as compared to normal conditions. For the vowels only, adaptation increased subsequent to a period of conversation with the bite block in place, suggesting that compensation may develop over time and that consonants may require a longer period of adaptation. The present follow-up investigation examined whether the acoustic differences across conditions were perceptually salient. Ten listeners performed an identification and a quality rating task for stimuli from the earlier acoustic study. Results revealed reductions in identification scores and quality ratings for a subset of the vowels and consonants in the bite-block conditions relative to the normal condition in the immediate compensation subtest. Ln the postconversation subtest, quality ratings for the fricatives in the bite-block condition remained low as compared to those in the normal condition. Perceptual results are compared to the previous acoustic data gathered on these stimuli. (C) 1996 Acoustical Society of America.