Abstract:

A primary issue in speech perception research is the apparent ``lack of invariance'' between the acoustic information in a signal and the listener's phonemic perception. The same intended phoneme can be produced with a wide range of acoustic values, and different intended phonemes may be produced with the same values. Although the existence of this variability is not in question, the degree to which listeners have to account for it is unclear. Some studies have attempted to measure the extent of this variability, but few have done so for fricatives, making it difficult to determine the degree to which individuals need to normalize fricative input for the individual talker. The current experiment attempts to rectify this hole in the literature by examining the fricative centroids for over 100 utterances beginning with /s/ and /(sh)/ from each of 20 different speakers. Although there was variability in the centroid values, the categories showed virtually no overlap within a talker. However, there was substantial overlap across talkers. This suggests that if listeners use centroids to cue the /s/--/(sh)/ distinction, they would first need to normalize the signal for the individual talker's frequency range. [Work supported by NIDCD Grant No. R01 DC00219 to SUNY at Buffalo.]