The time-course of linguistic interference during native and non-native speech-in-speech listening

Recognizing speech in a noisy background is harder when the background is time-forward than for time-reversed speech, a masker direction effect, and harder when the masker is in a known rather than an unknown language, indicating linguistic interference. We examined the masker direction effect when the masker was a known vs unknown language and calculated performance over 50 trials to assess differential masker adaptation. In experiment 1, native English listeners transcribing English sentences showed a larger masker direction effect with English than Mandarin maskers. In experiment 2, Mandarin non-native speakers of English transcribing Mandarin sentences showed a mirror pattern. Both experiments thus support the target-masker linguistic similarity hypothesis, where interference is maximal when target and masker languages are the same. In experiment 3, Mandarin non-native speakers of English transcribing English sentences showed comparable results for English and Mandarin maskers. Non-native listening is therefore consistent with the known-language interference hypothesis, where interference is maximal when the masker language is known to the listener, whether or not it matches the target language. A trial-by-trial analysis showed that the masker direction effect increased over time during native listening but not during non-native listening. The results indicate different target-to-masker streaming strategies during native and non-native speech-in-speech listening.