This study examines how language-minority and language-majority students and their teachers created a community of practice which allowed for meaningful participation of diverse learners in literacy practices, within a high school context in which language-minority students were historically marginalised. Drawing from ethnographic data, interviews and audio recordings of student interactions, we analysed how a community of practice was discursively constructed during an extracurricular, dual-language programme in one high school, in which students were learning English and Spanish. Our findings shed light on discourse patterns that reflected mutual engagement, joint enterprise, and a shared multilingual repertoire to build a community of practice that allowed students with diverse ethnolinguistic resources to participate actively in literacy and language knowledge construction. This study has implications for educators and researchers who seek to understand and cultivate contexts that counter the marginalisation of language learners and instead expand language and literacy learning opportunities for students becoming multilingual.