Lexically guided perceptual tuning of internal phonetic category structure

Abstract

Listeners use lexical information to retune the mapping between the acoustic signal and speech sound representations, resulting in changes to phonetic category boundaries. Other research shows that phonetic categories have a rich internal structure; within-category variation is represented in a graded fashion. The current work examined whether lexically informed perceptual learning promotes a comprehensive reorganization of internal category structure. The results showed a reorganization of internal structure for one but not both of the examined categories, which may reflect an attenuation of learning for distributions with extensive category overlap. This finding points towards potential input-driven constraints on lexically guided phonetic retuning.

Fig. 1.

(Color online) Mean goodness as /ʃ/ ratings are shown in (a) and mean /s/ responses are shown in (b) for experiment 1. (c) Mean goodness as /s/ ratings and (d) mean /s/ responses for experiment 2. Error bars indicate standard error of the mean.

Fig. 2.

(Color online) (a) Histograms for the center of gravity (in Hz) of the /ʃ/ and /s/ tokens presented to the /ʃ/-biasing and /s/-biasing training groups. The square black points at the top of each histogram indicate center of gravity for the six test tokens. (b) The same distributions plotted in terms of the natural versus modified versions of the tokens in each fricative category.