Morehead & Ingram (1973) revisited

The finding in Morehead and Ingram (1973) that children with a language impairment do better in the use of inflectional morphology than MLU-matched typically developing children has been in marked contrast to several subsequent studies that have found the opposite relationship (cf. review in Leonard, 1998). This research note presents a reanalysis of a subset of the original Morehead and Ingram data in an attempt to reconcile these contradictory findings. The reanalysis revealed that the advantage on inflectional morphology for children with language impairment was only on the progressive suffix, not on plural and possessive or on the verbal morphemes third-person present tense and past tense. The results of the reanalysis are in line with more recent research (e.g., Rice, Wexler, & Cleave, 1995). The resolution of these discrepant results highlights the critical roles that methodological issues play--specifically, how subjects are matched on MLU, how inflectional morphology is measured, and the selection of subjects with regard to age.