Input distribution influences degree of auxiliary use by children with specific language impairment

Children with specific language impairment (SLI) show a protracted period of inconsistent use of tense/agreement morphemes. The purpose of this investigation was to determine whether this inconsistent use could be attributed to the children's misinterpretations of particular syntactic structures in the input. In Study 1, preschool-aged children with SLI and typically developing peers heard sentences containing novel verbs preceded by auxiliary was or sentences in which the novel verb formed part of a nonfinite subject-verb sequence within a larger syntactic structure (e.g. We saw the dog relling). The children were then tested on their use of the novel verbs in contexts that obligated use of auxiliary is. The children with SLI were less accurate than their peers and more likely to produce the novel verb without is if the verb had been heard in a nonfinite subject-verb sequence. In Study 2, children with SLI and typically developing peers were tested on their comprehension of sentences such as The cow sees the horse eating. The children with SLI were less accurate than their peers and were disproportionately influenced by the nonfinite subject-verb clause at the end of the sentence. We interpret these findings within the framework of construction learning.