An examination of the morpheme BE in children with specific language impairment: the role of contractibility and grammatical form class.

This study examined the production of the morpheme BE, focusing on the influence of contractibility, the relationship between copula and auxiliary forms, and the occurrence of non-omission errors. Language samples collected from children with SU and from normal language learners at equivalent MLU levels were analyzed. Three levels of contractibility were examined: contractible, syntactically uncontractible, and phonetically uncontractible. Contractible contexts were produced significantly more accurately than uncontractible contexts by both groups. There was no difference between the two forms of uncontractibility. Furthermore, there were no significant interactions between language status and contractibility, suggesting that contractibility influenced both groups equally. Copula forms were produced more consistently than auxiliary. There was no interaction between BE type and language status. The groups did not differ in proportion or type of non-omission error. The results are discussed in relation to accounts of morphological deficits in SU.