Abstract
The paper reports on the results of a course of speech therapy for monozygotic twin boys. One of the boys, brother A, had been born with a cleft palate which had been surgically reconstructed. At the age of three years and ten months, the boys demonstrated similar phonological disorders with the main misarticulation involving glottal stops. Although the boys were assumed to share the same environmental and genetic factors, brother A had a mild delay in language development, and brother B was delayed in sociality. The misarticulation of glottal stops by brother B was regarded as having been learned from his brother and so his speech was expected to gradually improve naturally as his brother's speech improved. Consequently, systematic speech therapy was conducted only for brother A over a period of about two years from age three years and eleven months to age six. Throughout this period, the speech brother B was evaluated every three months. The brother B acquired normal articulation in a short period of time aided only by instruction at home by his mother.
