Neural machine translation (NMT) for low-resource languages such as Assamese and Bodo has seen dramatic quality improvements with large multilingual models like Multilingual Bidirectional and Auto-Regressive Transformer (mBART50) and IndicTrans2 multilingual Transformer model, but their parameter counts (often \(>1\) billion) make real-time, on-device deployment infeasible. Although Assamese and Bodo are not among mBART50’s pretraining languages, we first fine-tuned mBART50 on the AI4Bharat Samanantar Assamese–English and IndicTrans2-derived Bodo–English corpora to enable cross-lingual adaptation from related Indo-Aryan and Tibeto-Burman languages. We propose a novel two-stage approach that combines sparse Mixture-of-Experts (MoE) architectures with cross-lingual knowledge distillation to yield a 400-million-parameter student model that retains translation quality within approximately one Bilingual Evaluation Understudy (BLEU) point of its 1.3-billion-parameter teacher while reducing active computation per token by approximately four-fold. Our student uses a twelve-layer Transformer encoder–decoder: the first half of encoder and decoder layers remain standard, while the latter half incorporate sparsely activated Mixture-of-Experts (MoE) feed-forward blocks (four experts in the encoder with top-two gating; two experts in the decoder with top-one gating) and learnable language-prefix embeddings. We perform cross-lingual knowledge distillation, transferring both hard and soft labels from the fine-tuned mBART50 teacher on the AI4Bharat Samanantar Assamese–English corpus and IndicTrans2-derived Bodo–English data, with evaluation on the FLORES-200 multilingual benchmark. On a 10,000-sentence test set, our student achieves 34.5 BLEU compared with 35.2 BLEU for the teacher in Assamese–English, and 31.2 compared with 32.0 in Bodo–English, while running inference at approximately 24 ms per sentence on an RTX 3050 laptop GPU–about 280% faster than the dense teacher. To our knowledge, this is the first demonstration of cross-lingual MoE-based distillation for Indic NMT, enabling efficient, high-quality translation at the edge.