Number Dissimilarity Effects in Object-Initial Sentence Comprehension by German-Speaking Children With Specific Language Impairment.

Purpose This study examines the contribution of number morphology to language comprehension abilities among children with specific language impairment (SLI) and age-matched controls. It addresses the question of whether number agreement facilitates the comprehension accuracy of object-initial declarative sentences. According to the predictions of the structural intervention account for German, number agreement should assist the correct interpretation of object-initial sentences. Method This study examines German-speaking children with SLI and a control group of age-matched typically developing children on their sentence comprehension skills for auditory presented subject-verb-object and object-verb-subject (OVS) sentences. The sentences were manipulated with respect to the number properties of the noun phrases (e.g., one plural and one singular, or both singular) and the number agreement of the verb. Results The group of children with SLI demonstrated poorer comprehension accuracy in comparison to controls. Comprehension difficulty was limited to OVS sentences among children with SLI. In addition, children with SLI comprehended OVS sentences in which number agreement (with plural subject and verb inflection) indicated the noncanonical word order more accurately than OVS sentences with two singular noun phrases and therein did not differ from controls. Conclusion The study suggests that number agreement helps alleviate the difficulty with OVS sentences and enhances comprehension accuracy, despite the finding that children with SLI exhibit lower comprehension accuracy and more heterogeneous interindividual differences, relative to controls. Supplemental Material https://doi.org/10.23641/asha.13718029.