Preschoolers' Early Sentence Comprehension: Comparing Bilingual and Monolingual Children and the Role of Executive Function and Vocabulary Development.

Previous research into children's comprehension of syntactic structures has investigated early awareness of transitive and intransitive structures amongst monolingual children but research into bilingual children's understanding of the same sentence structures is lacking. This study compared 46 3-5-year-old bilingual children who spoke English and an additional language with 64 monolingual, English-speaking children, in their ability to associate transitive sentences with a causal scene, and intransitive sentences with a non-causal scene. In contrast to previous studies, the current study used still images instead of videos to create eight trials per structure, increasing the number of trials and testing structure as a within-participants manipulation. Children's vocabulary and executive function skills were also tested to observe interactions with the sentence comprehension task. Both groups showed the same overall pattern of effects, though the monolingual children were reliably more likely to match the causal scene to a transitive than bilingual children: Older children associated the transitive trials with causal scenes more than the intransitive trials, whereas 3-year-olds tended to associate both the transitive and intransitive sentences with causal scenes. Executive function performance did not differ between bilingual and monolingual children and was not related to sentence interpretation, but monolingual children had higher English vocabulary scores and children with greater vocabularies were better able to distinguish causal scenes as a match for transitive sentences. The results suggest that differences in comprehension of syntactic structures are more likely to be related to age and language ability, rather than differences in the number of languages spoken. SUMMARY: Bilingual and monolingual children showed similar patterns in their ability to comprehend transitive and intransitive sentences, though monolinguals more reliably associated transitives with causal scenes. 4- and 5-year-olds were better at associating transitives with causal scenes and intransitives with either causal or non-causal, whereas 3-year-olds associated both sentences with causal scenes. Age was a better predictor of differences in interpreting transitivity than the number of languages children speak. No executive function differences between bilinguals and monolinguals were found, monolinguals had larger English verb vocabularies; vocabulary was related positively to causal scene/transitive associations.