Specific language impairment in Swedish: the status of verb morphology and word order.

Several competing proposals have been offered to explain the grammatical difficulties experienced by children with specific language impairment (SLI). In this study, the grammatical abilities of Swedish-speaking children with SLI were examined for the purpose of evaluating these proposals and offering new findings that might be used in the development of alternative accounts. A group of preschoolers with SLI showed lower percentages of use of present tense copula forms and regular past tense inflections than normally developing peers matched for age and younger normally developing children matched for mean length of utterance (MLU). Word order errors, too, were more frequent in the speech of the children with SLI. However, these children performed as well as MLU-matched children in the use of present tense inflections and irregular past forms. In addition, the majority of their sentences containing word order errors showed appropriate use of verb morphology. None of the competing accounts of SLI could accommodate all of the findings. In particular, these accounts--or new alternatives-must develop provisions to explain both the earlier acquisition of present tense inflections than past tense inflections and word order errors that seem unrelated to verb morphology.