As immigration and mobility increases, so do interactions between people from different linguistic backgrounds. Yet while linguistic diversity offers many benefits, it also comes with a number of challenges. In seven empirical articles and one commentary, this Special Issue addresses some of the most significant language challenges facing researchers in the 21st century: the power language has to form and perpetuate stereotypes, the contribution language makes to intersectional identities, and the role of language in shaping intergroup relations. By presenting work that aims to shed light on some of these issues, the goal of this Special Issue is to (a) highlight language as integral to social processes and (b) inspire researchers to address the challenges we face. To keep pace with the world's constantly evolving linguistic landscape, it is essential that we make progress toward harnessing language's power in ways that benefit 21st century globalized societies.