A 3-years-and-11-months-old Japanese girl showed delayed language development and emotional disturbance and was believed to suffer from maternal deprivation. A treatment program was developed consisting of three kinds of therapy: (1) nondirective play therapy; (2) language training; and (3) counseling for the mother. The language training involved exposing the child to pictures, spoken language, and sign language for 30 words and asking the child to mimic the spoken and sign language. After learning 30 words in language therapy, her vocabulary at home reached 376 words and her listening attitude towards spoken language and other behavior were ameliorated. The child also learned to respond to the speech of the therapist, and she advanced in social maturity. The girl's mother became able to verbally stimulate her and treat her more adequately but still failed to communicate with the child in a satisfactory manner. The effectiveness of the therapy was attributed to the shapes and movements of the fingers in sign language, which represented words that could be easily caught visually by the child, thereby promoting the ability to respond to the sound of speech. (JDD)