Morpheme learning of children with specific language impairment under controlled instructional conditions

Three groups of children were exposed to instances of a novel morpheme under controlled experimental conditions. The performance of 32 children with specific language impairment (SLI), aged 5:0 to 7:0 years (years:months), was compared to that of 24 normally developing children matched for age and nonverbal ability and 20 younger normally developing children matched for language development and nonverbal ability. The children were taught under two instructional conditions that differed only in whether the child was asked to imitate the new language form after each instance (imitation) or just to observe its use (modeling). Consistent with past research (Connell, 1987b), the children with SLI performed significantly better under the imitation condition than under modeling, but the age-matched controls showed no difference in response to instruction. The performance of the language-matched controls was similar to that of the age-matched controls, suggesting that the instruction-specific effect for the children with SLI is not merely a function of general language immaturity. Although the superiority of the imitation condition for the children with SLI was evident for test trials requiring production of the new morpheme (as in past research), no such effect was evident for comprehension trials. This differing effect of output demands suggests that the SLI-specific response to instruction is not a matter of different mastery of the new rule but rather is specific to the need to access the newly induced rule on production trials. The accessing of phonological representations as a possible explanation for the effect is discussed.