The goal of this sabbatical is to author a monograph that synthesises and contextualises the considerable body of theoretical and empirical research on language maintenance that I, together with my collaborators, have contributed to the field over the past decade. Our research program has been guided by the question what fosters or impedes speakers to continue using their languages in light of competition from more powerful or dominant languages. This question is of crucial importance in our globalised world, where families from minority or migrant backgrounds often struggle to keep their languages in use and where many languages are endangered, as illustrated by the United Nation's declaration of the 'International Decade of Indigenous Languages' (2022–2032). The resulting volume will provide a state-of-the-art overview that integrates linguistic with social, affective, and educational dimensions of such language maintenance and examines it from both societal and individual vantage points. In order to do so, I will draw on our studies conducted in Sweden and around the world, including rigorously executed transnational studies allowing for comparative birds-eye analyses across countries. Such comparisons are still uncommon in the field due to their methodological challenges, yet afford us to better understand how societal conditions might modulate language maintenance and provide directions for future research.