On Language Deficits and Modality in Children With Down Syndrome: A Case Study of Twins Bilingual in BSL and English

Abstract

It has been suggested that there may be an age advantage for the acquisition of sign language relative to spoken language for 2 reasons: (1) language in the visual-motor modality may be easier to access, recall, and produce than language in the auditory-vocal modality and (2) the continuity in form between gesture and sign language may promote the transition from prelinguistic to linguistic communication. These suggestions have provided the impetus for many language intervention programs for children with intellectual impairments. This article reports on hearing identical female twins with Down's syndrome who have deaf parents. The twins are bilingual, having been exposed since infancy to both spoken English and British Sign Language (BSL). Starting at age 10, the twins were tested for non-verbal intelligence, receptive vocabulary, grammatical structure, articulation, auditory and visual memory, and gestural (manual) expression. Analyses of tests and spontaneous data reveal a high degree of fluency in gesture but impairments in both languages, suggesting that the fundamental problems of children with Down syndrome are not modality specific and that there are discontinuities between gesture and language.