Abstract
Almost all hearing impaired children are born to hearing parents. Moreover, in Japan since there are few hearing impaired teachers for the hearing impaired in the kindergarten of a school for the hearing impaired, the children acquire sign language with little contact with a native speaker of sign language. Given this, this study longitudinally observed 5 year-old hearing impaired children who were born to hearing parents, and were enrolled in the kindergarten of a school for the hearing impaired and instructed by hearing teachers, to clarify the sign language acquisition process. We videotaped hearing impaired children's free play over half a year, and analyzed the hearing impaired child's sign language utterances. Consequently, the following points became clear.
At first, hearing impaired children communicate with gestures different from gestures used by their hearing age peers. Next, the gestures and sign language that a hearing impaired child uses have many features grammatically similar to the sign language used by adult hearing impaired. Lastly, it was clarified that a hearing impaired children elaborate ambiguous input as sign language from their hearing parents or their teachers to be "language", and acquires it as the first language by the hearing impaired children's group power. A review may be required for what should be taught in a school for the hearing impaired for sign language, compared with the sign language acquisition process of a hearing impaired child with a hearing impaired parent based on the findings achieved in this study.
