Abstract
Studies on language acquisition in infants have recently used brain imaging methods, such as NIRS (near infrared spectroscopy) and EEG (electroencephalography) measurements, as well as classical behavioral methods. These studies have demonstrated developmental changes in neural and behavioral responses during speech processing. In this article, I review some studies on Japanese infants and address development of behavioral and brain responses to Japanese lexical pitch accent and phonemic vowel length underlying the change in speech perception abilities.