Recent studies have projected that by the end of this century between half and up to 95% of the linguistic diversity in the world will disappear or become severely endangered. In the last four decades, the Latin American region, home to more than 500 Indigenous languages, has introduced intercultural bilingual education policies aimed at protecting Indigenous children's right to learn in their mother tongue and contributing to language revitalization. Yet, little is known about how to meaningfully teach biliteracy competencies that simultaneously fulfill the goals of Indigenous cultural revitalization and strategic economic and political participation in national society. Centering the voice of Indigenous language teachers and preservice teachers, drawing from the continua of biliteracy framework, and building on an on-going research partnership, this design-based research (DBR) study was implemented to reflect on teaching biliteracy practices in Spanish and Indigenous language (Qom and Wichi) courses at teaching institutions in Northern Argentina. Data were collected during 24 weeks in 2022-2023, includes storytelling interviews, video recorded classroom observations, student group interviews, co-design sessions, fieldnotes, and artifacts, which were coded employing a deductive codebook. Findings showed how Qom language teachers have become biliterate by their own efforts, in an interplay of adversity and resilience, developing a teaching approach centered on nurturing Indigenous identities. Their teaching is shaped by previous experiences alphabetizing adult Qom speakers or Spanish early literacy methods which do not correspond with their current students, Qom young adults increasingly preferring Spanish. Current biliteracy practices identified showed the need to expand and incorporate best practices on how to teach agglutinative languages effectively and develop dialectal intelligibility. There is an institutional responsibility to provide a coherent and cohesive language learning experience to Indigenous students, which calls for joining efforts between criollos and Indigenous teachers, centering their efforts on biliteracy. Finally, a DBR approach grounded in Indigenous research methodologies is a promising mode of operation to generate knowledge needed by the urgent demands of language revitalization which also makes use and contributes to research and practice on multilingual context in the global sphere. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]