Capturing Complex Syntax Development: Comparing Late Talkers to Children with Typical Language
Complex syntax proficiency is an understudied but integral aspect of preschool grammatical development. Children classified as late talkers at two years of age lag behind their same-aged peers with typical language in the preschool years on measures of grammatical development. In this dissertation, we characterized the complex syntax development of late talkers from 30 to 66 months as compared to same-aged peers with typical language development. Participants were selected from the Ellis Weismer Corpus of language samples available from the Child Language Data Exchange System (CHILDES) and comprised two groups: late talkers (n = 26) and typical language (n = 16). Language samples (50 utterances) were coded for complex syntax; multiple variables were derived to describe complex syntax quantity and diversity and complex syntax vocabulary (i.e., subordinate conjunctions, complement clause verbs). Complex syntax quantity and diversity increased across time. Between-group differences were evident for complex syntax quantity variables only at 30 months. In contrast, between-group differences for the complex syntax diversity variable were evident at 30, 54, and 66 months. Complex syntax type diversity is particularly sensitive to between-group differences in brief language samples. Between-group differences in complex syntax development in late talkers as compared to children with typical language support future studies of the mechanisms of individual differences in complex syntax development.