Yi–Han–English trilingual education in junior middle schools under two models in Liangshan

China is a multilingual nation and the current education policy allows minority languages to be used in schooling alongside Mandarin and English in minority regions. Liangshan Yi Autonomous Prefecture implements trilingual education through two models. Model One schools prioritise the Yi language as the primary medium of instruction, whereas Model Two schools rely predominantly on Mandarin. This qualitative case study examines how Yi, Mandarin, and English are used in classroom instruction and informal school spaces in two junior middle schools. Drawing on observations, interviews, and documents, the analysis interprets how practices align with policy along a translanguaging continuum from separation to integration. Across both schools, subject teaching clustered at the separation and translation end. Mandarin served as the default language for explanation and task guidance, Yi was recruited mainly for terminology and literacy, and English was largely confined to grammar translation routines. Integration was common in informal talk across Yi, Sichuanese, and Mandarin but appeared only rarely in instruction. These patterns diverge from trilingual policy intentions and help to explain limited student investment in written Yi. The paper identifies adjustments to assessment, materials, staffing, and classroom design to support planned integration and narrow the gap between practice and policy.