Ability to perceive non-native contrasts with natural and synthetic speech stimuli

Abstract

The perception of the distinction between /r/ and /l/ by native speakers of American English and of Japanese was studied using natural and synthetic speech. The American subjects were all nearly perfect at recognizing the natural speech sounds while there was substantial variation among the Japanese subjects in their accuracy of recognizing naturally produced /r/ and /l/. A logit model, which additively combined the acoustic information conveyed by F1-transition duration and by F3-onset frequency, provided a good fit to the perception of synthetic /r/ and /l/ by the American subjects. There was substantial variation among the Japanese subjects in whether the F1 and F3 cues had a significant effect on their classifications of the synthetic speech; greater use of the F1 and F3 cues in classifying the synthetic speech sounds was positively related to accuracy in recognizing natural /r/ and /l/. These results show that tests using natural and synthetic speech tap into the same variation of ability in perceiving the non-native /r/–/l/ contrast by Japanese speakers. The relation between performance on natural and synthetic speech also provides external validation of the logit model by showing that it predicts performance beyond the data to which it was fit.