The dissertation focuses on one Truku (Indigenous) village in eastern Taiwan and aims to understand the processes and possibilities of bottom-up language revitalization. In 2012, the National Geographic Genographic Legacy Fund supported the village to start a community-driven language revitalization initiative. Drawing on scholarship guided by critical Indigenous research methodologies, critical sociocultural approaches to language policy and planning, and sociocultural approaches to learning, this study is an attempt to generate qualitative ethnographic research to facilitate local praxis. The major findings are four: Firstly, after decades of colonialism, villagers' lived experiences and language ideological standpoints vary significantly across generations and households, which constraints the possibility of collective endeavors. Secondly, building on previous scholars' emphasis on "ideological clarification" prior to language revitalization, I identify the dimension of embodied ideological differences, using cultural historical activity theory to illustrate how certain "mainstream" artifacts (e.g. orthography) can confine orally dominant elders' capacity to contribute. In a similar vein, by closely examining children's voices and language performances, I highlight children's theory of language as relationship-building and a theory of learning as participation in communities of participation, which stand in stark contrast to adult educators' constructs of acquisition and proficiency in traditional SLA. Finally, inspired by children and elders' voices, methodologically I argue for a relational conceptualization of agency and propose a relationship-oriented language revitalization framework. Such framework values and incorporates existing social relationships in praxis, and requires researchers and practitioners to humbly recognize the work of power in social relations and develop a trusting, reflective bond with the villagers before rushing to impose agendas. This dissertation contributes to the scholarship of language policy and planning by incorporating sociocultural learning theories designed to generate praxis-oriented analysis. By contextualizing identity and SLA processes in an Indigenous context, the study also illuminates the affective dimension of language learning and education. Overall this study offers valuable insights for scholars, educators, and practitioners interested in community-based language education. Equally important, this research represents the voices of multiple generations of Truku people, deeply committed to ensuring that future generations remain connected to their heritage language, knowledge system, and ways of being.