Terminology-Aware Retrieval-Augmented Knowledge Distillation for Biomedical Neural Machine Translation
Summary
Compact student models trained with standard knowledge distillation (KD) keep all their knowledge in fixed parameters. This limits them in specialised domains such as biomedical translation, where parallel data is scarce and specialised terminology must be translated correctly. The authors address this for French-to-English biomedical NMT by combining few-shot KD with retrieval-augmented generation (RAG).
At inference time, a Small Transformer student draws on an external non-parametric memory. The memory holds training sentence pairs and translations produced by the larger teacher. For each input, the student fetches related examples and briefly fine-tunes itself on them, a form of test-time adaptation. The paper compares plain semantic retrieval with a hybrid strategy that ranks candidates by terminology overlap.
The terminology-aware variant beats semantic-only retrieval and the distilled baseline. It reaches or exceeds teacher quality while keeping the speed of a small model. This matters for deploying efficient MT in domains where terminology is critical and data is limited.
Key points
- The best configuration uses terminology-overlap retrieval over DistilledMemory153K and reaches a mean score of 80.07 at k = 15. The mean combines SacreBLEU, chrF++, COMET, BERTScore and BLEURT.
- At its peak, this configuration scores chrF++ 84.80 and COMET 90.45.
- It improves on the strongest semantic retrieval setup by 0.73 points. It improves on the distilled student baseline by 3.24 points, a relative gain of 4.22%.
- Semantic retrieval (DistilledMemory760K / DistilledMemory153K) tends to keep improving up to k = 31. The terminology-aware method peaks earlier, with k between 12 and 19, and shows diminishing returns beyond that.
- Bootstrap resampling with compare-mt confirms that the terminology-based students significantly outperform the quantized teacher on SacreBLEU (p < 0.05). Test-time adaptation uses only 10 gradient steps.
Cite
@inproceedings{zafar2026terminology,
title = {{Terminology-Aware Retrieval-Augmented Knowledge Distillation for Biomedical Neural Machine Translation}},
author = {Zafar, Maria and Bakkali, Souhail and Haque, Rejwanul},
booktitle = {Proceedings of the 26th Annual Conference of the European Association for Machine Translation (Volume 1)},
year = {2026},
url = {https://aclanthology.org/2026.eamt-1.26/}
}References
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