The effect of regional and non-native accents on word recognition processes: a comparison of EEG responses in quiet to speech recognition in noise

Previous work has shown that both the speed and accuracy of word recognition can be reduced if a talker has a regional or non-native accent, particularly under noisy conditions. This study investigated whether the reduced intelligibility of some accents in noise are related to aspects of speech processing in quiet. Our goal was to see if difficulties processing accented speech under adverse listening conditions can be revealed in quiet using electrophysiological methods. Participants heard English sentences in a standard, regional or non-native accent. Behavioural measures found listeners had a strong intelligibility advantage for the standard accent when mixed with noise, replicating previous work. However, differences in processing the accents were less clear using the EEG measures. We found a significant Phonological Mapping Negativity (PMN) elicited by phonological anomalies, as well as an N400 effect, which is related to semantic anomalies, but although both responses were somewhat larger for the standard accent, there was more overlap in the EEG responses for different accents than for speech-in-noise recognition. More work is needed, but it is plausible that some of the difficulty that listeners have with accents under noise may be related to the same accent processing difficulties that occur in quiet.