A seemingly simple everyday experience such as speaking multiple languages has considerable consequences for brain structure, function and cognition. However, exactly how this experience affects the brain is still poorly understood, given that many of the findings to date in this field have been variable. Part of this variability likely comes from the fact that multilingualism is a spectrum of experiences which contribute to aspects of brain plasticity. To move research in this domain forward, a unified way to examine multilingual experiences, and their effects on brain plasticity, is needed. The present project addresses this need by developing a consolidated framework that links together distinct multilingual experiences and outcomes and outlines a clear set of methods to test this framework.