Thesis advisor: C. Patrick Proctor / Traditionally strict language separation policies in dual language bilingual education (DLBE) programs reflect parallel monolingualism and have been criticized as failing to recognize the sociolinguistic realities of bilingual students (García & Lin, 2017). To leverage bilingual learners’ full linguistic repertoires as resources, this study explored how Sánchez, García, and Solorza’s (2018) translanguaging allocation policy could be strategically and purposefully designed in a third grade Mandarin/English DLBE classroom where the majority of the students were English-dominant speakers. Taking the form of participatory design research (Bang & Vossoughi, 2016), I (as a researcher) and a Mandarin teacher worked together to co-design translanguaging documentation, translanguaging rings, and translanguaging transformation spaces across different content areas – Chinese Language Arts, Science, and Social Studies. During the process, we also engaged in equitable forms of dialogue and listening to openly discuss, negotiate, and develop our translanguaging co-stance in iterative ways. Data collection included classroom and design meeting recordings, observational field notes, and teacher and students’ artifacts and interviews throughout the school year of 2018-19. Inductive and deductive coding were adopted for data analysis. Findings revealed that translanguaging pedagogies took many shapes based on contextual factors, such as the different pedagogical purposes and curricular demands across content areas. Students were able to develop deeper content understandings, build cross-linguistic connections, and develop their bi/multilingual identities and critical consciousness in those flexible bilingual spaces. Findings also demonstrated that the ideological (re)negotiation between the researcher and the teacher was a bumpy and discursive journey, replete with tensions, confusions, and difficult conversations. Overall, it was a balancing act to create translanguaging spaces while maintaining the language-minoritized (Mandarin) space and privileging students’ use of Mandarin given the societal dominance of English. This study provides implications for new theoretical and pedagogical understandings of translanguaging, and suggests that researcher-teacher collaboration provides a promising way to generate evidence-based, practitioner-informed, and context-appropriate knowledge for DLBE curricular and pedagogical improvements. / Thesis (PhD) — Boston College, 2020. / Submitted to: Boston College. Lynch School of Education. / Discipline: Teacher Education, Special Education, Curriculum and Instruction.