Present tense be use in young children with specific language impairment: less is more

A well-known characteristic of children with specific language impairment (SLI) is a significant deficit in grammatical morphology production compared with younger, language-matched, typically developing children. This is true for present tense be (am, is, are), as well as other inflectional morphemes. However, grammatical morpheme learning by children with SLI may vary depending on developmental stage. Participants were 8 boys with SLI (42 to 58 months old with mean length of utterances [MLUs] < or = 3.0 morphemes) and 14 MLU-matched controls (girls and boys; mean age of 27 months). These groups were younger and had lower MLUs than groups from oft-cited studies (e.g., Cleave and Rice, 1997; Leonard, Bortolini, Caselli, McGregor, and Sabbadini, 1992; Leonard, Eyer, Bedore, and Grela, 1997; Rice, Wexler, and Hershberger, 1998). The SLI group had a significantly higher percentage of be use in obligatory contexts (46%) than did the younger, typically developing children (27%). This pattern of better performance in grammatical morphology by SLI groups than controls has been reported. Ingram (1972) and Morehead and Ingram (1973) found similar results for children with language impairment in early-MLU stages. Although findings are presented with caution, they afford an opportunity to consider the nature of SLI. If SLI represents a general processing limitation, then that limitation might enable the language learner with SLI to acquire some initial morphological mappings with relative success. This apparent paradox, which also is evident in normal language acquisition, has been termed less is more by Newport (1990). Limited perception and memory force attention to smaller pieces of the input, and these constraints simplify the task for the language learner. SLI is compared with a chronically constrained system that initially assists the learner to achieve basic form-function mappings but ultimately hinders mastery of English morphology.