Non-native perception of regionally accented speech in a multitalker context

Noisy listening conditions are challenging to non-native listeners who typically perform poorly while attending to several competing talkers. This study examined whether nonnative listeners are able to utilize dialect-related cues in the target and in the masking speech, even if they do not reach the proficiency level of the native listeners. 35 Indonesian-English bilinguals residing in the United States were presented with speech stimuli from two American English dialects, General American English and Southern American English, which were systematically varied both in the target sentences and in 2-talker masking babble at three sound-to-noise ratios (SNR). We found that the non-native listeners were (1) sensitive to dialect-specific phonetic details in speech of competing talkers and (2) performed in a manner similar to native listeners despite their apparent deficit. However, their performance differed significantly when the speech levels of the competing talkers were equal (0 dB SNR). The differential sensitivity of non-native listeners may reflect their inability to separate utterances of competing talkers when there is not enough contrast in their voice levels. In turn, the lack of sufficient contrast may reduce their ability to benefit from the phonetic-acoustic details necessary to encode the signal and comprehend a message.