Together with my former MA student, Danai Tsinivits, we just had a paper accepted for a special issue of the journal Applied Psycholinguistics on Capturing and quantifying individual differences in bilingualism. Our study used parental report data to investigate the language development of bilingual toddlers growing up with Greek and Dutch as their two languages and living in the Netherlands. Children either came from ‘one parent, one language’ families or families were both parents spoke Greek. We found that in general toddlers with older siblings heard than their first-born peers, but no difference was found between the two groups (with vs. without older siblings) for parental input only. Toddlers with older siblings also used more Dutch at home. Their Dutch receptive and productive vocabulary and morphosyntactic complexity was also more advanced. Despite such differences, however, toddlers with older siblings scored comparably to toddlers without older siblings on all measure of Greek. We discuss these findings in light of factors such as family constellation, parental language proficiency, bilingual parenting strategies, and the wider sociolinguisitc context. The paper is currently in production and I’ll post a link as soon as it’s online.