In this introduction, we situate the theme issue within a growing body of research on Indigenous youth language practices, communicative repertoires, and ideologies, articulating points of intersection in scholarship on Indigenous and immigrant youth bilingualism. Our geographic focus is North America. Ethnographic studies from the Far North to Mexico counter stereotypical assumptions that Indigenous youth simply orient away from local community practices toward "killer languages" in communities experiencing language shift, offering nuanced understandings of the ways in which young people negotiate relationships of power, assumptions about language, and diminishing opportunities for ancestral language learning in rapidly changing sociolinguistic ecologies. Drawing on the contributing authors' longstanding engagements with language planning in the communities represented, we emphasize transformative possibilities as well as the theoretical, methodological, and ethical considerations involved in youth language research in contemporary Indigenous communities.