Increasingly, speakers of minoritized languages around the world are becoming uprooted due to economic pressures, political forces, and environmental destabilization. As communities leave their traditional homelands, they often experience accelerated language shift. Although youth are in a critical position to further transmit their languages to future generations, the roles of youth are often overlooked in language documentation and revitalization. This often has to do with ideologies that privilege monolingual practices and view the linguistic differences of heritage language speakers as incomplete or incorrect. Such ideologies circulate not only among language users, but among language researchers as well. Community-based language work that centers multilingual youth can support outcomes aligned with community goals of language maintenance. This dissertation brings together tools and perspectives from language documentation, sociocultural linguistics, applied linguistics, heritage language research, language ecology, and translanguaging approaches to multilingualism in an effort to support the language maintenance goals of diasporic Nuu Savi (Mixtec) community partners within a community-centered framework of collaborative language work. The approach, which I term diaspora linguistics, centers multilingual youth in order to holistically understand language structure, variation, ideology, and sociolinguistic context, and to produce applied research outcomes, in Indigenous diaspora settings. The context for this dissertation is a longstanding linguistic research collaboration between members of the UCSB Department of Linguistics and affiliates of a community non-profit organization that serves the Indigenous Mesoamerican immigrant community in Ventura and Santa Barbara counties in California's Central Coast region. In particular, this dissertation focuses on nine individuals from an extended family, all of whom speak a Tu'un Savi (Mixtec language) variety from the municipality of San Martin Peras in Oaxaca, Mexico, which is the plurality variety on the Central Coast. I use multiple methods, including an interview-based survey, a questionnaire, and two narrative elicitation tasks, to gain insight into speakers' linguistic practices and language attitudes. First, drawing from a recent large community language survey, I provide demographic information about the broader community and the local language situation. Responses from the survey shed light on community members' ethnolinguistic identities and highlight the importance of language maintenance to a majority of respondents. The surveys reveal several ideologies about multilingualism: an assumption that young people do not speak Tu'un Savi; or, if they do, that they speak differently or deficiently due to an ideology that prioritizes monolingual-like linguistic performance. Then, using responses to a family language questionnaire, I connect ideologies about multilingualism and speakerhood to individual family members' linguistic experiences and migration histories. The analysis shows that participants who experienced monolingual language development have a coordinate bilingual profile and are less likely to acknowledge the Tu'un Savi proficiencies of younger people, while those who experienced bilingual language development at an early age have a compound bilingual profile and are more likely to recognize Tu'un Savi as a language of young multilinguals. Against this ideological backdrop, I analyze variation in loanword usage across generations of the same family using semi-structured narrative elicitation tasks. The results show that loanword usage is a shared but largely idiosyncratic practice that is inversely correlated with age. The example of a jar in the elicitation materials highlights the range of reference strategies used by participants. Youth may hesitate or avoid using a loanword when a native word is not known; young adults creatively apply a range of native lexical items to the referent, and adults unproblematically use loanwords, even in contexts of verbal art characterized by stylistic repetition. The dissertation closes with the description of a hypothetical lesson plan for multilingual youth that draws from the data and analyses of preceding chapters to support the linguistic practices and ethnolinguistic identities of multilingual youth. As a whole, the dissertation aims to address the varied and multiple empirical and applied issues intertwined in language work in Indigenous diaspora contexts, while facilitating the centering of collaborator and community goals in the research agenda rather than the goals of the academic researcher. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.] more...