Volume 109, Issue 2, February 2001
Index of content:
- SPEECH PERCEPTION 
Influence of fundamental frequency on stop-consonant voicing perception: A case of learned covariation or auditory enhancement?109(2001); http://dx.doi.org/10.1121/1.1339825View Description Hide Description
For stimuli modelingstop consonants varying in the acoustic correlates of voice onset time (VOT), human listeners are more likely to perceive stimuli with lower as voiced consonants—a pattern of perception that follows regularities in English speech production. The present study examines the basis of this observation. One hypothesis is that lower enhance perception of voiced stops by virtue of perceptual interactions that arise from the operating characteristics of the auditory system. A second hypothesis is that this perceptual pattern develops as a result of experience with -voicing covariation. In a test of these hypotheses, Japanese quail learned to respond to stimuli drawn from a series varying in VOT through training with one of three patterns of -voicing covariation. Voicing and varied in the natural pattern (shorter VOT, lower in an inverse pattern (shorter VOT, higher or in a random pattern (no -voicing covariation). Birds trained with stimuli that had no -voicing covariation exhibited no effect of on response to novel stimuli varying in VOT. For the other groups, birds’ responses followed the experienced pattern of covariation. These results suggest does not exert an obligatory influence on categorization of consonants as [VOICE] and emphasize the learnability of covariation among acoustic characteristics of speech.
Discrimination of non-native consonant contrasts varying in perceptual assimilation to the listener’s native phonological system109(2001); http://dx.doi.org/10.1121/1.1332378View Description Hide Description
Classic non-native speech perception findings suggested that adults have difficulty discriminating segmental distinctions that are not employed contrastively in their own language. However, recent reports indicate a gradient of performance across non-native contrasts, ranging from near-chance to near-ceiling. Current theoretical models argue that such variations reflect systematic effects of experience with phoneticproperties of native speech. The present research addressed predictions from Best’s perceptual assimilation model (PAM), which incorporates both contrastive phonological and noncontrastive phonetic influences from the native language in its predictions about discrimination levels for diverse types of non-native contrasts. We evaluated the PAM hypotheses that discrimination of a non-native contrast should be near-ceiling if perceived as phonologically equivalent to a native contrast, lower though still quite good if perceived as a phonetic distinction between good versus poor exemplars of a single native consonant, and much lower if both non-native segments are phonetically equivalent in goodness of fit to a single native consonant. Two experiments assessed native English speakers’ perception of Zulu and Tigrinya contrasts expected to fit those criteria. Findings supported the PAM predictions, and provided evidence for some perceptual differentiation of phonological, phonetic, and nonlinguistic information in perception of non-native speech. Theoretical implications for non-native speech perception are discussed, and suggestions are made for further research.