Babbling of prelinguistic mentally retarded children.

Our goal was to illuminate the role of canonical (well-formed syllabic) babbling in the development of speech by mentally retarded children. We made tape recordings of vocalizations produced by 36 prelinguistic children (17 to 62 months of age) who were students in a full-time cognitive and linguistic intervention program, and we obtained data on their developmental ages. The great majority of the retarded children, in spite of their linguistic handicaps, produced canonical babbling. The proportion of canonical babbling was less, however, for a number of the retarded children than for a sample of nonretarded infants in the canonical babbling stage. A low correlation of babbling and developmental age suggested substantial independence of cognitive development and babbling among the retarded children.