Developmental changes of cerebral responses to native and non-native phonemic contrast

While newborn infants discriminate speech sounds from languages that they have never heard, 6-month-olds demonstrate the beginnings of vowel classification specific to their native-language. The neuronal correlates involved in such a dramatic perceptual reorganization process, however, are not well understood. Using near-infrared spectroscopy (NIRS), this study compares the neural responses of Japanese infants at 3-4 months and 7-8 months of age as well as of adults to native ([i] vs. [] ) and non-native vowel contrasts ([] vs. [u]) within pseudo-word contexts. The findings demonstrated longitudinal developmental changes of functional temporal cortex asymmetries associated with the exposure of the native language