Abstract
Many people with Down syndrome suffer from speech and hearing disorders such as delayed speech, articulation disorder, hearing impairment and stuttering. The author provided the speech therapy for 5 years to a boy with Down syndrome who had only 17 expressive words at 6:11 years old. Although he acquired a maximum of 5-word sentences, his articulation disorders were severe. He spent many sessions to acquire phonemes except labial consonants and fricative consonants. The errors of phonemes were mainly of distortion. He could not discriminate between voiced and voiceless phonemes and could not correct his errors. But by the use of letters he could identify them. As a result, his speech and articulation disorders are considered to be caused by the disorder of his development of the phonetic system, and he can not image and identify the precise phonemes. Therefore, to speech, using visual stimuli such as written letters or cued speech will be useful for children with Down syndrome who have severe speech handicaps.
