Tencent Open-Sources HY-MT1.5: 440MB Offline Translation Model That Outperforms Google Translate Across 33 Languages

Tencent / GitHub·medium signal

Tencent Hunyuan Team open-sourced HY-MT1.5-1.8B-1.25bit, a 440MB on-device translation model supporting 33 languages and 1,056 translation directions. Uses Sherry 1.25bit quantization (accepted at ACL 2026) with 3:4 fine-grained sparsity to compress from 3.3GB FP16 to 440MB with minimal accuracy loss. Outperforms Tower-Plus-72B, Qwen3-32B, and commercial APIs including Microsoft Translator. Runs fully offline on phones via custom STQ mobile CPU kernel — no subscription, no internet required.