Environmental Factors and Sentence Complexity in Child Second Language Acquisition

Variability in the linguistic proficiency of bilinguals is often associated with differences in exposure to the target language (Gathercole, 2014; Unsworth, 2016). The characteristic variation of environmental factors in child second language (L2) acquisition makes this population ideal for investigating how external components affect language learning (Paradis & Grüter, 2014). Research on input effects in child L2 acquisition often comprise quantitative, qualitative, and distal aspects of exposure. Previous studies investigating the effects of environmental factors in the morphosyntactic domain for child L2 learners have mostly focused on investigation of production of a number of complex structures (e.g. Armon-Lotem et al., 2011; Paradis & Kirova, 2014; Paradis et al., 2017; Unsworth, 2014; 2016). In the present study, we investigate the comprehension of L2 sentence structures ranging in complexity (active and passive voice, and subject and object relative clauses), and how their interpretation by child L2 learners is impacted by a number of environmental factors (length of L2 exposure; L2 language use at home; richness of the L2 environment; maternal education; and maternal L2 proficiency). Length of exposure in L2 acquisition refers to the amount of time the individual has been exposed to the target language and is traditionally measured in years or months by taking age of first meaningful exposure to the L2 from the child’s chronological age (Roesch & Chondrogianni, 2016; Unsworth, 2016). In child L2 acquisition, and where the child is of pre-school age, significant and consistent exposure (also referred to as meaningful exposure) typically occurs on commencing nursery or primary school (Paradis, 2011). Previous research focusing on the effect of length of L2 exposure and sentence structures has revealed both positive (e.g. Paradis et al., 2017) and negative (e.g. Unsworth, 2016) effects. L2 language use at home comprises a fine grained measure of quantitative language input which involves the calculation of detailed L2 exposure time and use, to allow a more comprehensive representation of the individual’s L2 exposure (Paradis, 2011). Fine grained measures are typically evaluated through