Abstract
Neurophysiological studies of infant speech suggest that mismatch responses (MMRs) have predictive value for later language. Their value, however, is diminished because unexplained differences in the MMR patterns are seen across studies. The current study aimed to identify the functional nature of infant MMRs by recording event-related-potentials (ERPs) to an infrequent English vowel change in internal or final positions of a sequence of ten vowels in six-month-old monolingually and bilingually exposed infants. Increased negativity of the MMR (infrequent minus frequent) was found in final compared to internal positions and correlated with an index of increased attention to the final position. This pattern helps explain the overall greater negativity to the speech sounds in the bilingually exposed female infants. These findings substantially advance our understanding of neural indices of speech perception development and show promise for furthering our understanding of bilingual language development.