TUM-Heilbronn: WMT26 Multilingual Instruction Shared Task

Jen-Chien Hou, Tsedeniya Kinfe Temesgen, Alexander Fraser


Abstract
This paper describes the TUM-Heilbronn sys- tem submission to the WMT26 Multilingual Instruction Shared Task (MIST). The MIST covers three tasks: context-based question an- swering, open-ended generation, and cross- lingual summarization to evaluate the multi- lingual instruction-following ability of large language models. We fine-tune Qwen3.5-9B- Instruct on 27 diverse languages, across 10 dif- ferent writing scripts. Our model outperformed 6 of the 15 models submitted to this shared task. Moreover, we ranked first in truthfulness (i.e., decline to answer when the context lacks sufficient information) on the context-based question-answering task. Cross-lingual sum- marization remains a challenging task for all submitted models, with the lowest performance observed among the three tasks.
Anthology ID:
2026.wmt-main.128
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:
1925–1932
Language:
URL:
https://aclanthology.org/2026.wmt-main.128/
DOI:
Bibkey:
Cite (ACL):
Jen-Chien Hou, Tsedeniya Kinfe Temesgen, and Alexander Fraser. 2026. TUM-Heilbronn: WMT26 Multilingual Instruction Shared Task. In Proceedings of the Eleventh Conference on Machine Translation, pages 1925–1932, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
TUM-Heilbronn: WMT26 Multilingual Instruction Shared Task (Hou et al., WMT 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.wmt-main.128.pdf