Although bilingual language research has increased considerably over the past few decades, there is still much controversy regarding the mechanisms of bilingual language acquisition. The present work aims to provide insights into potential mechanisms of bilingual language learning by utilizing a novel word-learning paradigm in which monolingual and bilingual adults (Experiment 1) and children (Experiment 2) are taught two novel languages either simultaneously or sequentially. Results suggest that bilingual language learning may be occurring in a domain specific manner dependent on learning order, previous language experience, and the participant’s age. Keywords: novel word learning; order effects; second language acquisition; bilingualism