Improving Term Evaluation in Machine Translation: Variation Matters

Nicolas Dahan, Ziqian Peng, François Yvon, Rachel Bawden


Abstract
Terminology evaluation in machine translation (MT) usually assumes a single correct target form per source term, yet human translators routinely introduce variation that current metrics penalize as inconsistency. We examine how to account for this variation in document-level MT evaluation in English–French scientific translation, combining glossary-based accuracy, translation consistency, and a new cross-term variation (CTV) diagnostic measure that captures whether variation relationships are preserved across languages. On two parallel corpora translated by four MT systems, we find that (1) MT systems generate less target-side variation than human translators; (2) transfer patterns strongly depend on the variation type; (3) consistency rankings vary with the choice of metric; and (4) constraining MT with a glossary improves accuracy and consistency but degrades CTV by suppressing valid variation. We argue for variation-aware evaluation that conditions consistency penalties on whether target-side variation mirrors source-side variation.
Anthology ID:
2026.amta-research.7
Volume:
Proceedings of the 17th Conference of the Association for Machine Translation in the Americas (Volume 1: Research Track)
Month:
August
Year:
2026
Address:
Québec City, Canada
Editors:
Eleftheria Briakou, Jeremy Gwinnup, Shivali Goel
Venue:
AMTA
SIG:
Publisher:
Association for Machine Translation in the Americas
Note:
Pages:
101–134
Language:
URL:
https://aclanthology.org/2026.amta-research.7/
DOI:
Bibkey:
Cite (ACL):
Nicolas Dahan, Ziqian Peng, François Yvon, and Rachel Bawden. 2026. Improving Term Evaluation in Machine Translation: Variation Matters. In Proceedings of the 17th Conference of the Association for Machine Translation in the Americas (Volume 1: Research Track), pages 101–134, Québec City, Canada. Association for Machine Translation in the Americas.
Cite (Informal):
Improving Term Evaluation in Machine Translation: Variation Matters (Dahan et al., AMTA 2026)
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PDF:
https://aclanthology.org/2026.amta-research.7.pdf