Acoustic and articulatory asymmetries in fricative-vowel and vowel-fricative productions

Abstract

When synthetic noise replaces the natural friction in FV syllables and VF syllables, the influence of the vocalic segment on the perception of the noise as /s/ or /∫/ is greater for the FV syllables [S. D. Soli and V. A. Mann, J. Acoust. Soc. Am. Suppl. 1 71, S75 (1982)]. The acoustic and articulatory bases of this perceptual asymmetry were examined. Mean formant tracks displaying confidence intervals and amplitudes were computed for natural FV and VF syllables, where F = /∫/ and /s/, and V = /ɑ/ and /u/. FV and VF transitions were equally stable, although FV transitions exhibited larger coarticulatory differences due to fricative context. FV transitions also occurred during the highest amplitude portion of the vocalic segment, while VF transitions occurred as voicing amplitude was decreasing rapidly before the upcoming voiceless fricative. These acoustic differences would lead to larger vowel context effects for FV syllables. Thus the perceptual asymmetries appear to be a consequence of differences in the organization and timing of the supralaryngeal and laryngeal events which produce initial and final voiceless fricatives. [Supported by NICHD.]