Learning and generalization components of morphological acquisition by children with specific language impairment: is there a functional relation?

Children with specific language impairment (SLI) have particular difficulty acquiring bound morphemes. To determine whether these morphological deficits spring from impairments of rule-induction or memory (storage/access) skills, 25 preschool-age children with normal language (NL) and 25 age-matched children with SLI were presented with a novel vocabulary and novel bound-morpheme learning task. A chi square analysis revealed that the children with SLI had significantly lower vocabulary learning levels than NL children. In addition, there was tentative evidence that a dependency relationship existed in some children between success in vocabulary learning and proficiency in generalizing a trained bound morpheme to untrained vocabulary stems. These findings are predicted by the storage/access but not the rule-induction theory of specific language impairment. They suggest that intervention targeting bound-morpheme skills acquisition in children with SLI might include attention to vocabulary development.