Intelligibility of English phonemes in noise for native and non-native listeners

The effect of noise and presentation level on the perception of English consonants by native listeners and non-native listeners were examined. English words contrasting in /r/-/l/, /b/-/v/ and /s/-/th/ sounds, which are known to be difficult to distinguish for native speakers of Japanese, were presented to both native speakers of American English (AE listeners) and those of Japanese (J) in white noise and in pink noise at sytematically changed signal-to-noise ratios (SNR). Words were also presented at various presentation levels. The effects of noise and presentation level differed by phonetic contrast and language group. The /b/-/v/ and /s/-/th/ contrasts were more affected by noise at high SNRs, while /r/-/l/ was tolerant for noise when the SNR was higher than -3 dB. The presentation level affected AE listeners' identification of /b/-/v/, but not of other contrasts. J listeners' perception was affected less than that of AE listeners, possibly because the flooring effect for J listeners' identification performance was low, even for original stimuli.