As a transcultural K-Pop fandom,아미 [A.R.M.Y.] perform out-of-school, Web 2.0 English[es] composing to cooperatively translate, exchange and broker content for parasocially relating to/with members of the supergroup 방탄소년단 [BTS] and to/with each other. Using critical linguistic ethnography, this study traces how 아미 microbloggers’ digital conversations embody Jenkins’ principles of participatory fandom and Wenger’s characteristics of communities of learning practice. By creating Wei’s multilingual translanguaging spaces, 아미 assemble interest-based collectives Pérez González calls translation adhocracies, who collaboratively access resources, produce content and distribute fan compositions within and beyond fandom members. In-school K-12 and secondary learning writing Composition and Literacy Studies’ theory, research and pedagogy imagine learners as underdeveloped novices undergoing socialization to existing“native” discourses and genres and acquiring through “expert” instruction competencies for formal academic and professional “lived” composing. Critical discourse analysis of 아미 texts documents diverse learners’ initiating, mediating, translating and remixing transmodal, plurilingual compositions with agency, scope and sophistication that challenge the fields’ structural assumptions and deficit framing of students. 아미 ontic languaging practices and nonhierarchical networking invalidate perduring expert needs discourse and the standard teaching writing model of task-driven, factitious procedures as means not to empower learners, but to preserve power. Furthermore, the intercultural translinguality practiced by 아미 repudiates the unacknowledged, nativist ideology of English Exceptionalism infecting English research, scholarship and pedagogical epistemologies. Reengineering English classrooms to be sites for cultivating learner motility, with both teaching and learning writing enacting cooperative translanguaging praxes is advocated. Preliminary experiments in revising instruction and assessment for high school and college composition to legitimize composers’ interest-driven assemblages and sharing of critical interpretation and textual production are described.