Balancing Fluency and Adherence: Hybrid Fallback Term Injection in Low-Resource Terminology Translation

Kurt Abela, Marc Tanti, Claudia Borg


Abstract
Integrating domain-specific terminology into Machine Translation systems is a persistent challenge, particularly in low-resource and morphologically-rich scenarios where models lack the robustness to handle imposed constraints. This paper investigates the trade-off between static dictionary-based data augmentation and dynamic inference constraints (Constrained Beam Search). We evaluate these methods on two high-to-low resource language pairs: English-Maltese (Semitic) and English-Slovak (Slavic). Our experiments reveal a dichotomy: while dynamic constraints achieve near-perfect Terminology Insertion Rates (TIR), they drastically degrade translation quality (BLEU) in low-resource settings, breaking the fragile fluency of the model. Conversely, static augmentation improves terminology adherence on unseen terms in Maltese (4% 19%), but fails in the context of a highly inflected language like Slovak. To resolve this conflict, we propose Hybrid Fallback Term Injections, a strategy that prioritizes the fluency of static models while using dynamic constraints as a safety net. This approach recovers up to 90% of missing terms while mitigating the quality degradation of pure constraint approaches, providing a viable solution for high-fidelity translation in data-scarce environments.
Anthology ID:
2026.loresmt-1.6
Volume:
Proceedings for the Ninth Workshop on Technologies for Machine Translation of Low Resource Languages (LoResMT 2026)
Month:
March
Year:
2026
Address:
Rabat, Morocco
Editors:
Atul Kr. Ojha, Chao-hong Liu, Ekaterina Vylomova, Flammie Pirinen, Jonathan Washington, Nathaniel Oco, Xiaobing Zhao
Venues:
LoResMT | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
78–86
Language:
URL:
https://preview.aclanthology.org/ingest-eacl/2026.loresmt-1.6/
DOI:
Bibkey:
Cite (ACL):
Kurt Abela, Marc Tanti, and Claudia Borg. 2026. Balancing Fluency and Adherence: Hybrid Fallback Term Injection in Low-Resource Terminology Translation. In Proceedings for the Ninth Workshop on Technologies for Machine Translation of Low Resource Languages (LoResMT 2026), pages 78–86, Rabat, Morocco. Association for Computational Linguistics.
Cite (Informal):
Balancing Fluency and Adherence: Hybrid Fallback Term Injection in Low-Resource Terminology Translation (Abela et al., LoResMT 2026)
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https://preview.aclanthology.org/ingest-eacl/2026.loresmt-1.6.pdf