Recognition of gated verbs by children with Grammatical-Specific Language Impairment: Effects of inflection and frequency

A common feature of language disorders, particularly in English, is an impairment in inflectional morphology. One view claims that this deficit is caused by impaired speech processing and resulting impoverished phonological representations. We investigated the accuracy of spoken word recognition in Specific Language Impairment (SLI) using a successive forward gating paradigm, with target verbs manipulated for frequency and past tense inflection. Children with Grammatical-SLI were compared to age and language controls. We scored responses according to (1) proportion of gates to the first correct response, (2) proportion of gates to the first of three consistently correct responses. G-SLI children generally performed at the same level as age and vocabulary controls, although worse than age controls on uninflected verbs with respect to the second criterion, indicating that they activated the correct word at the same point, but took longer to reach a consistent response. Low frequency and inflection of the target word did not disadvantage G-SLI children to a greater extent than any of their controls. These results do not support the hypothesis that G-SLI children's morphological impairment is caused by poor acoustic-phonetic processing.