Factors affecting accuracy of past tense production in children with specific language impairment and their typically developing peers: the influence of verb transitivity, clause location, and sentence type.

Purpose: The author examined the influence of sentence type, clause order, and verb transitivity on the accuracy of children's past tense productions. All groups of children, but especially children with specific language impairment (SLI), were predicted to decrease accuracy as linguistic complexity increased.

Method: The author elicited past tense productions in 2-clause sentences from 5- to 8-year-old children with SLI (n=14) and their typically developing peers (n=24). The target sentences varied in the type and obligatory nature of the second clause and the number of arguments.

Results: On average, 85% of the responses across all groups and sentence types contained 2 clauses. Fewer 2-clause sentences were produced in the complement clause condition than in the other conditions. Sentence type and clause order, but not argument structure, influenced use of past tense. Children with SLI had a similar but less accurate profile as compared with the age-matched group. The younger mean length of utterance (MLU)-matched group reflected decreased accuracy with each additional source of linguistic complexity.

Conclusions: Increased syntactic difficulty decreases use of morphology for all children, supporting the hypothesis that processing demands influence morphological accuracy. MLU-matched children, but not children with SLI, were more affected by changes in linguistic complexity. Further work on age-related changes in sentence production is necessary.