The Interface between the Lexicon and Finiteness Marking in Specific Language Impairment

Abstract

Inconsistent omission of finiteness markers is a clinical marker for Specific Language Impairment (SLI). A similar pattern of omission is observed during normal development. Potential limiting factors during this stage of variability are not well understood. This research considered lexical representations, indexed by neighborhood density, as one limiting factor. Study 1 examined the effect of density on variable production of a finiteness marker by 4- and 5-year olds with SLI and by typically developing 3-year olds. The results showed that density was a limiting factor for typically developing children, but not for children with SLI. Study 2 examined the effect of density on finiteness growth in a learning task by children with SLI. Results showed differences in growth for children exposed to dense and sparse verbs. The combined results suggest that lexical representations interact with finiteness to differentially impact production and growth. Differences in density effects across groups are discussed.