This study of a postcolonial site engages with epistemic justice from the perspective of language. It understands epistemic justice as relating to issues of knowledge, understanding, and participation in communicative practices. It suggests that monoglossic language-in-education policies, often colonial in origin, constitute a form of epistemic injustice by denying learners the opportunity to learn in a familiar language and removing their ability to make epistemic contributions, a capacity central to human value. It further suggests that translanguaging in formal school settings is for the most part geared towards a monolingual outcome, that is, towards accessing knowledge in an official language. This unidirectional impetus means that translanguaging remains an affirmative rather than transformative strategy, leaving underlying hierarchies of value and relations of knowing unchanged. In contrast, this study presents linguistic ethnographic data from a three-year pilot project in Cape Town where primary school learners could choose their medium of instruction to Grade 6 and use all languages in subject classrooms. It analyses how a Grade 6 learner used laminated, multilingual, affective and epistemic stances to construct others as knowers, negotiate epistemic authority, and promote solidarity. It proposes that, in so doing, she constructed new decolonial relations of knowing and being. It further proposes that the shift from a monolingual to a multilingual episteme, which substantially improved educational performance overall, also enabled the emergence of politically fragile yet institutionally robust social, epistemic, and moral orders from below, orders that could lay the basis for greater epistemic justice. Towards Epistemic Justice: Language, Identity, and Relations of Knowing in Post-colonial Schools Multilingualism and identities in and out of school: urban youth on the Cape Flats