Educators, scholars, and community activists recognize that immersion education is a key means to restoring Indigenous and other heritage languages. But language maintenance and revitalization involve many complex issues, foremost may be the lack of local professional development opportunities for potential language teachers. In Alaska, the Second Language Acquisition Teacher Education (SLATE) project was designed to enable Indigenous communities and schools to improve the quality of native-language and English-language instruction and assessment by focusing on the elimination of barriers that have historically hindered degree completion for Indigenous and rural teachers. The Guided Research Collaborative (GRC) model, was employed to support the development of communities of practice through near-peer mentoring and mutual scaffolding. Through this important new model, teachers of both the heritage language, in this case Central Yup’ik, and English were able to situate their professional development into a larger global context based on current notions of multilingualism. In Communities of Practice contributors show how the SLATE program was developed and implemented, providing an important model for improving second-language instruction and assessment. Through an in-depth analysis of the program, contributors show how this project can be successfully adapted in other communities via its commitment to local control in language programming and a model based on community-driven research. Communities of Practice demonstrates how an initial cohort of Yup’ik- and English-language teachers collaborated to negotiate and ultimately completed the SLATE program. In so doing, these educators enhanced the program and their own effectiveness as teachers through a greater understanding of language learning. It is these understandings that will ultimately allow heritage- and English-language teachers to work together to foster their students’ success in any language.