This study investigated the relationships between home language learning activities and vocabulary in a sample of monolingual native Dutch (n = 58) and bilingual immigrant Moroccan-Dutch (n = 46) and Turkish-Dutch (n = 55) 3-year-olds, speaking Tarifit-Berber, a nonscripted language, and Turkish as their first language (L1), respectively. Despite equal domain general cognitive abilities, Dutch children scored higher than the bilingual children on a L1 vocabulary test, and Moroccan-Dutch children had higher second language (L2) vocabulary skills compared to Turkish-Dutch children. Multigroup analyses revealed strong impact on both L1 and L2 skills of language specific input in literate and oral activities. Finally, indications were found of positive cross-language transfer from L1 to L2 as well as competition between L1 and L2 input. (Contains 6 tables and 3 figures.)