Neural responses to morphosyntactic violations in foreign accented speech

When comprehending speech, listeners extract information regarding the speaker's characteristics, such as their sex, nationality or socioeconomic status, from the speech signal. This speaker-identity information is integrated on-line during speech processing, influencing how listeners process both the phonological and semantic content of the utterance. However, little is known as to whether morphosyntactic processing is also influenced by the integration of of the speaker's identity. This study used the event-related potential technique to examine whether listeners' (n-30) neural responses to morphosyntactic violations (here subject-verb agreement errors) were modulated by the presence of speaker-identity information in the form of a foreign accent. The results demonstrated that the presence of a foreign accent did affect the neural responses observed for the violations, with errors of the commission type (where a superfluous morpheme was present) eliciting an N400 effect in native speech but an anterior negativity in foreign accented speech. However, omission errors (where a required morpheme was missing) elicited no violation effect for either speaker. The unexpected presence of an N400 effect was attributed to shallow syntactic processing and a possible priming effect caused by the presence of semantic violations in the experimental stimuli. The lack of effect observed for omission errors was attributed to the relative lack of perceptual salience of this error type. Some individual variation in the neural responses was observed, which was weakly related to participants' empathy levels. Overall, the results provided evidence that speaker-identity information is indeed integrated on-line during morphosyntactic processing.