Noncategorical perception of a voiced-voiceless fricative continuum

Abstract

A nine-token synthetic VOT continuum for /feɪl/-veɪl/ was constructed with 10-ms steps in fricative voicing. Perceptual studies revealed better-than-chance discrimination between pairs of tokens labeled /feɪl/, chance discrimination between pairs of tokens labeled /veɪl/, and a slight peak in the discrimination function at the labeling boundary between /feɪl/ and /veɪl/. To better understand the noncategorical discrimination data, relative onset time (ROT) difference limens were measured for a range of durations of a 100-Hz sawtooth waveform, which served as the analog for voicing in the speech continuum. ROT difference limens increased systematically with increasing duration of the standard sawtooth waveform. The ROT data suggest that better-than-chance discrimination near the /feɪl/-endpoint and chance discrimination near the /veil/-end-point reflect larger absolute difference limens for onset of voicing as voicing duration was increased from /feɪl/ to /veɪl/. Traditional phonetic processes presumably account for the slight peak in the discrimination function at the labeling boundary between the /feɪl/ and /veɪl/categories. [Research supported by NIH.]