Even with a high degree of sensorineural hearing loss, the conversational effects from wearing a hearing aid start with voice imitation. In approach of rehabilitation of children with hearing loss, the phonological language system of the mother tongue is established by supplying voice, finger characters, and with the use of symbols, such as the child’s native written language. This paper focuses on a test subject (Child A) who had little voice mimicking until 7 years old. For this subject, the priority of communication was focused on sign language and finger characters, rather than voice usage. In one episode, Child A, in one session during an examination of Sound composition, was seen showing a conflicting reaction to the different nasal and non-nasal sounds. In another, after a session while pronouncing syllables, Child A was seen to have actively begun vocal imitations. After seeing such changes in Child A, the author decided to investigate this child’s vocal Imitation development.