Faces with foreign accents: An event-related potential study of accented sentence comprehension

Mounting Event-Related Potential (ERP) research testing the neurocognitive processes of foreign- and native-accented speech comprehension shows that listeners process foreign-accented speech in qualitatively and quantitatively different ways from native-accented speech. Previous ERP research has presented listeners with foreign- and native-accented sentences only, devoid of any cues to the speaker's identity. Additional cues about the foreign-accented speaker identity, such as faces, may be useful in aiding listeners' processing, potentially reducing differences between neurocognitive processes associated with foreign-accented and native-accented speech comprehension. This study tested whether providing listeners with extra-linguistic face cues to the speakers' identity affects the ERP correlates of grammatical and semantic processing of foreign-accented and native-accented sentences. Specifically, we presented listeners with face cues to speaker identity followed by native- and foreign-accented sentences that were identical to Grey and Van Hell (2017), who did not provide face cues. To elucidate the effects of face cues, we compared the present study's Face Cue data with the Grey and Van Hell (2017) No Face Cue data. For grammar processing, the results showed a biphasic Nref-P600 for native-accented speech and a P600 for foreign-accented speech in the Face Cue group. In the No Face Cue group, results for grammar processing showed an Nref for native-accented speech and no significant ERP effects for foreign-accented speech. This result indicates that face cues were effective in aiding processing of foreign-accented sentences. For semantic processing, there were robust N400 effects for native-accented speech and delayed N400s for foreign-accented speech in the Face Cue and No Face Cue groups. This pattern indicates that the extra-linguistic face cue to foreign-accented speaker identity did not affect semantic processing. Overall, the results provide neurocognitive evidence that the integration of speaker and face information aids listeners during the processing of foreign-accented speech, particularly for grammatical processing.