MAGADIR at WMT 2026: Cross-System QE Re-ranking and Entity-Aware Selection for Low-Resource Arabic-English Translation

Hossam Boudraa


Abstract
We present MAGADIR’s submissions to the WMT 2026 Low-Resource Arabic–Asian Language Translation Shared Task for English–Arabic translation. Our systems combine a small official parallel corpus, parameter-efficient adaptation of open-weight multilingual models, and segment-level, reference-free quality-estimation re-ranking over heterogeneous cross-system candidate pools. For Arabic-to-English translation, the pool includes supervised LoRA-adapted NLLB and Hunyuan-family models alongside zero-shot Hunyuan/HY-MT and Gemma models. For English-to-Arabic, we select among zero-shot Hunyuan/HY-MT, Gemma, Aya, and NLLB candidates. The Arabic-to-English primary system uses MetricX-24-QE together with a Wikidata-derived entity-recall floor that vetoes candidates omitting recognized proper names before quality estimation determines the final output; the English-to-Arabic primary uses COMETKiwi without an entity constraint. On the official Challenge Test, the Arabic-to-English primary achieves 27.45 BLEU, 56.61 chrF, and 81.94 COMET, while the English-to-Arabic primary obtains 14.59 BLEU, 51.48 chrF, and 83.88 COMET. Relative to our own single-model contrastives, QE-guided cross-system selection improves COMET by up to 1.94 points for Arabic-to-English and 0.81 points for English-to-Arabic, although some contrastive systems retain stronger lexical-overlap scores. This exposes a persistent trade-off between neural adequacy objectives and reference-based surface metrics. A post-hoc matched control separates the Arabic-to-English entity floor from the otherwise confounded change in QE utility. The floor accounts for 83% of the entity-recall gain while changing only 7% of outputs and imposing effectively no COMETKiwi cost (+0.0002); the switch from COMETKiwi to MetricX rewrites 74% of outputs and accounts for the full −0.0085 COMETKiwi difference. Our audit also identifies an important limitation: on approximately 65% of entity-bearing segments, no candidate preserves every recognized entity in canonical form, leaving the veto with no feasible alternative. These findings motivate routine reference-free entity auditing, more diverse candidate pools, expanded gazetteer coverage, and transliteration-aware entity matching for QE-selected translation systems.
Anthology ID:
2026.wmt-main.169
Volume:
Proceedings of the Eleventh Conference on Machine Translation
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Barry Haddow, Tom Kocmi, Philipp Koehn, Christof Monz
Venues:
WMT | WS
SIG:
SIGMT
Publisher:
Association for Computational Linguistics
Note:
Pages:
2280–2297
Language:
URL:
https://aclanthology.org/2026.wmt-main.169/
DOI:
Bibkey:
Cite (ACL):
Hossam Boudraa. 2026. MAGADIR at WMT 2026: Cross-System QE Re-ranking and Entity-Aware Selection for Low-Resource Arabic-English Translation. In Proceedings of the Eleventh Conference on Machine Translation, pages 2280–2297, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
MAGADIR at WMT 2026: Cross-System QE Re-ranking and Entity-Aware Selection for Low-Resource Arabic-English Translation (Boudraa, WMT 2026)
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PDF:
https://aclanthology.org/2026.wmt-main.169.pdf