Effects of vowel context upon labelling the /s/-/š/ continuum

Abstract

Although they are true obstruent consonants, fricatives have not been studied as exhaustively as stop consonants. In the following study, we report findings on perception of a set of VC fricative syllables. Specifically, a continuum of fricatives ranging from /s/ to /š/ were synthesized after close examination of natural fricatives. The fricatives were embedded in coarticulated /i/C and /u/C frames. Identification functions, i.e., phoneme labelling, were done for each vowel environment using panels of 10 listeners each. In addition, response time measures and quality ratings were made of the stimuli. In a second study, an ABX paradigm was used to generate discrimination functions. The crossover point for /s/-/š/ labelling, and the magnitude and steepness of discrimination and identification functions were then tested to determine (1) to what degree fricative perception is “categorical” and (2) to what degree labelling boundary depends upon context. Results indicate that there is a substantial context dependency in the labelling crossover point, and that a good case can be made for quasicategorical perception of the /s/-/š/ fricative continuum.