Input and uptake for complex syntactic structures in child language development: Implementing structural priming with diverse learner populations.

Language development depends on both the quantity of linguistic input children receive and their ability to uptake input, yet the relationship between these two factors remains unclear. This study adopted the structural priming paradigm to examine how input and uptake shape syntactic development in three groups of Mandarin-speaking children aged 5-9 years (N = 75, Nfemale = 39): neurotypical monolinguals (optimal input and uptake), monolinguals with Developmental Language Disorder (optimal input, reduced uptake), and Mandarin-English heritage bilinguals (reduced input, optimal uptake). All groups had acquired the target non-canonical structures (the BA-, BEI-, and OSV-constructions). However, reduced input and reduced uptake were associated with distinct production patterns. Heritage bilinguals produced more canonical structures (the SVO-construction), whereas monolingual children, particularly those with Developmental Language Disorder, favoured the BA-construction, suggesting differences in underlying learning mechanisms and production strategies that may be shaped by their language (learning) experience. Moreover, while richer input enhanced uptake, reduced input did not diminish it, suggesting input quantity and processing ability play separable yet interacting roles in development.