Mean length utterance in Brazilian children: a comparative study between Down syndrome, specific language impairment, and typical language development.

Purpose: To describe the linguistic performance of Brazilian Portuguese-speaking children with Down syndrome by analyzing their Mean Length Utterance; to compare their performance to that of children with Specific Language Impairment and Typical Development; and to verify whether children with Down syndrome present developmental language delay or disorder.

Method: Participants were 25 children with Down syndrome (Research Group), matched by mental age to a Control Group of typically developing children, and to a Control Group of children with Specific Language Impairment. Participants were divided into subgroups, according to age range (three, four and five years). Speech samples were collected for the Research Group, and the Mean Length Utterance was analyzed for morphemes and words.

Results: Differences were observed between the performance of the Research Group and both Control Groups, and the former presented inferior Mean Length Utterance values for all age ranges, characterizing a delay in grammar and general language development.

Conclusion: The description of the linguistic abilities of Brazilian Portuguese-speaking children with Down syndrome indicated important grammatical deficits, especially regarding the use of functional words.