CUNI and Phrase at WMT25 MT Evaluation Task

Miroslav Hrabal, Ondrej Glembek, Aleš Tamchyna, Almut Silja Hildebrand, Alan Eckhard, Miroslav Štola, Sergio Penkale, Zuzana Šimečková, Ondřej Bojar, Alon Lavie, Craig Stewart


Abstract
This paper describes the joint effort of Phrase a.s. and Charles University’sInstitute of Formal and Applied Linguistics (CUNI/UFAL) on the WMT25Automated Translation Quality Evaluation Systems Shared Task. Both teamsparticipated both in a collaborative and competitive manner, i.e. they eachsubmitted a system of their own as well as a contrastive joint system ensemble.In Task~1, we show that such an ensembling—if chosen in a clever way—canlead to a performance boost. We present the analysis of various kinds ofsystems comprising both “traditional” NN-based approach, as well as differentflavours of LLMs—off-the-shelf commercial models, their fine-tuned versions,but also in-house, custom-trained alternative models. In Tasks~2 and~3 we showPhrase’s approach to tackling the tasks via various GPT models: Error SpanAnnotation via the complete MQM solution using non-reasoning models (includingfine-tuned versions) in Task~2, and using reasoning models in Task~3.
Anthology ID:
2025.wmt-1.68
Volume:
Proceedings of the Tenth Conference on Machine Translation
Month:
November
Year:
2025
Address:
Suzhou, China
Editors:
Barry Haddow, Tom Kocmi, Philipp Koehn, Christof Monz
Venue:
WMT
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
934–944
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URL:
https://preview.aclanthology.org/ingest-emnlp/2025.wmt-1.68/
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Cite (ACL):
Miroslav Hrabal, Ondrej Glembek, Aleš Tamchyna, Almut Silja Hildebrand, Alan Eckhard, Miroslav Štola, Sergio Penkale, Zuzana Šimečková, Ondřej Bojar, Alon Lavie, and Craig Stewart. 2025. CUNI and Phrase at WMT25 MT Evaluation Task. In Proceedings of the Tenth Conference on Machine Translation, pages 934–944, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
CUNI and Phrase at WMT25 MT Evaluation Task (Hrabal et al., WMT 2025)
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https://preview.aclanthology.org/ingest-emnlp/2025.wmt-1.68.pdf