Dual language input and the impact of language separation on early lexical development

We examined properties of the input and the environment that characterize bilingual exposure in 11-month-old infants with a regular exposure to French and an additional language, and their possible effects on receptive vocabulary size. Using a diary method, we found that a majority of the families roughly followed a one-parent-one-language approach. Yet, the two languages co-occurred to various extents within the same half-hour both within and across speakers. We used exploratory correlation analyses to examine potential effects of the dual input on the size of infants' vocabularies. The results revealed some evidence for an impact of language separation by speakers.