A recent movement in cognitive neuroscience is the study of brain networks through functional and effective connectivity. The brain networks approach has already found its influences in the study of the neurobiology of language, but has yet to impact research in the neurocognition of bilingualism and second language. In this article, we briefly review some preliminary evidence in this emerging field and suggest that the understanding of the dynamic changes in brain networks enables us to capture second language learning success, thereby providing new insights into the neural bases of individual differences, neuroplasticity, and bilingualism.