A longitudinal study of the acquisition of language by two German-speaking children with cochlear implants and of their mothers' speech.

The development of language in two children with cochlear implants was analyzed using longitudinal data of videorecorded mother-child interactions. Recordings were made over a period of 14 months for child A and over a period of 3 years for child B. At the beginning of data collection the children were 2;11 and 3;7 respectively. Results reveal substantial differences between the two children and their mothers. Child B was slow in acquiring grammar, with vocalizations and non-linguistic communicative behavior persisting. The child also used language in a labeling function. Child B's MLU (mean length of utterance) never exceeded 2.7 morphemes and his syntax remained rudimentary. Child A had a highly imitative style at the beginning, but then progressed to the spontaneous use of multi-word utterances very quickly, reaching an MLU of 5.6 morphemes in less than 2 years. Child A progressed to correct morphology and a fairly complex syntax. The children's mothers differed with respect to their use of exaggerated intonation patterns, repetitions and expansions, the use of labeling, questions, and directives. Results are discussed in terms of the influence of children's information processing styles and mothers' speech input.