The influence of deviant maternal input on the development of language during the preschool years

Language development of five two-year-old hearing children of deaf parents was studied longitudinally. These results were compared with the normal language developmental literature, and analyzed in relation to the form of the mothers' oral input. Three of the deaf mothers were less than 15% intelligible and their MLU was less than 2.0. The children spent less than 20 hours weekly with normal speakers. Frequency and proportion measurements were used to compare these children's utterances with those of children from normal-hearing households studied by Lois Bloom and Roger Brown. The observed children's utterances contained similar categories of semantic-syntactic relations and as many syntactic utterance types as children from hearing households. Furthermore, the children were appropriately acquiring grammatical morphemes in relation to their MLU. The overwhelming majority of the children's utterances adhered to a subject-verb-object order of constituents, and discourse interaction (the ability to add information to another's utterance) was developing. The results indicate that children, when cognitively ready, need little exposure to the normal model language to learn to speak during the early stages of development.