Where does interlanguage speech intelligibility benefit come from: Shared phonological knowledge or exposure to accented speech

Previous studies in interlanguage speech intelligibility benefit (ISIB) did not separate the effects of shared knowledge of L1 in non-native talkers from those of listeners through extensive exposure to accented L2 speech, which is crucial to the mechanism underlying ISIB. This preliminary study attempts to tease apart the two by comparing perception accuracy of Mandarin-accented English words among Mandarin listeners, English listeners who have not learned Mandarin, and learners of Mandarin who had varied amount of exposure to Mandarin-accented English. Consistent with previous studies, Mandarin listeners showed highest accuracy. For word pairs contrasting voiceless and voiced velar stop in coda position, learners of Mandarin who had greater exposure to Mandarinaccented English showed higher accuracy than learners who had less exposure. These results support ISIB for Mandarin and suggest that ISIB is more likely to stem from exposure to accented L2 speech than from shared knowledge alone.