Children's auditory lexical decisions: a limited processing capacity account of language impairment

Twenty-three school-age children with language impairments (LI) and 46 typically achieving children participated in 2 auditory lexical decision tasks. Effects of phonological opacity (i.e., stress and vowel changes involved in forming derivatives from a base word) on word recognition were investigated. In one task, children made lexical decisions about phonologically transparent real derivatives (e.g., hatless) and pseudo derivatives (e.g., *quickless). In this task, children with LI showed only subtle deficits compared to their chronological-age (CA) peers. In the other task, children made lexical decisions about phonologically opaque real derivatives (e.g., acidity) and pseudo derivatives (e.g., *combinity) as well as transparent derivatives. In this task, children with LI were substantially less accurate than were CA children in identifying phonologically opaque real derivatives and were slower to do so than both CA and language-age (LA) children. Children in the LI and LA groups were slower than children in the CA group to identify phonologically opaque pseudo derivatives. These results are interpreted within a limited processing capacity account of language impairment.