Children acquiring a language have to master the basic rhythms of their native language.
Recent research in infant speech perception have shown that the rhythm may be one of the first properties of a language a baby pays attention to, and this could play a critical role in early stages of language acquisition. Japanese is a mora-timed language. Japanese children must learn what counts as a unit in determining the basic rhythm of the language. In recent years, we have been exploring this issue through various experiments with Japanese infants as well as young children. In this talk, I will share some of the data we have gathered over the years, and discuss the potential implications of these data with respect to general issues of Japanese phonology and language acquisition.