The effects of experimental variables on the perception of American English /r/ and /l/ by Japanese listeners

The effects of variations in response categories, subjects’ perception of natural speech, and stimulus range on the identification of American English /r/ and /l/ by native speakers of Japanese were investigated. Three experiments using a synthesized /rait/-/lait/ series showed that all these variables affected identification and discrimination performance by Japanese-subjects. Furthermore, some of the perceptual characteristics of /r/ and /l/ for Japanese listeners were clarified: (1) Japanese listeners identified some of the stimuli of the series-as/w/.(2). Apositive correlation between the perception of synthesized stimuli and naturally-spoken stimuli was found. Japanese listeners who were able to easily identify naturally spoken stimuli perceived the synthetic series categorically but still perceived a /w/ category on the series. (3) The stimulus range showed a striking effect on identification consistency; identification of /r/ and /l/ was strongly affected by the stimulus range, the /w/ identification less so. This indicates that Japanese listeners tend to make relative judgments between /r/ and /l/.