Published online by Cambridge University Press: 25 November 2019
Although many researchers appeal to performance limitations to account for children’s non-adult-like use of language, few studies have explicitly linked specific cognitive abilities to specific dimensions of language. This study investigated a well-studied underextension in children’s language involving linguistic aspect and tested participants in an aspectual comprehension task as well as a series of assessments evaluating neurocognitive and linguistic skills. Adults (N = 32) and 5-year-old children (N = 32) participated. The results for the children replicated the classic pattern of underextension, with children showing an uneven pattern of success even though all items were equally grammatical. In addition, children’s skill with items that involved overriding lexical information in favor of morphological information was predicted by their performance on an inhibitory control task while children’s skill with items that involved integrating contextual world knowledge was predicted by their performance on a receptive vocabulary task. These results demonstrate how specific dimensions of linguistic processing are supported differentially and sensibly by specific dimensions of cognition.