Abstract

A 15-year-old adolescent with an intellectual disorder received intensive parent-implemented cognitive-behavioral treatment (Zelazo et al., 1984) designed to elicit expressive language skills. The results indicate the acquisition of imitative and spontaneous words and word approximations, and the acquisition of spontaneously generated two- and three-word approximation phrases with correct word order. Finally, increased attention, impulse control, language comprehension, and attention to and compliance with verbal instructions were evident during the post-treatment conventional assessment. The findings suggest the beginning of the use of verbal communication in an adolescent beyond the critical period for language acquisition and the acquisition of the prerequisites necessary for success on conventional tests of mental development. The usefulness of the notion of a critical period for language acquisition is discussed.