V: GENERAL DISCUSSION.

Abstract

Ours is the first study to directly measure the relative contribution of linguistic distance to the acquisition of a bilingual toddler's two languages, which was the aim of Study 1. To address this question we tested 372 24-month-olds learning British English and one of 13 target Additional Languages. We found that a higher phonological overlap between these Additional Languages and British English led to higher levels of Additional Language CDI vocabulary production. Similar effects in comprehension were found for our other measures of linguistic distance, namely degree of similar in morphological complexity and word order. Importantly, linguistic distance contributed unique variance even when other key factors (proportion of English in child-directed input, proportion of English in parental overheard speech and gender) were entered into the same model.