LiLa at WMT 2026 General MT Task: Exploring Beyond NMT and Learning the Limits of LLM Adaptation for Ligurian and Ladin

Mirelle Bueno, Lucas Domingues, Samuel Frontull, Jean Maillard, Sushil Garg


Abstract
We describe LiLa, our submission to the constrained track of the WMT 2026 General Machine Translation Task. Motivated by recent advances in large language models (LLMs) and their increasing availability as open models, we investigate the adaptation of LLMs for Ligurian and Ladin, two low-resource languages included in the shared task. We evaluate several adaptation strategies for Gemma-4, including Instruction Tuning (IT-only), continuous pre-training followed by Instruction Tuning (CPT+IT), and Low-Rank Adaptation (LoRA), and compare them with a dedicated encoder-decoder pipeline based on fine-tuned No-Language Left Behind (NLLB) models. Our experiments show that, under the evaluated conditions, fine-tuned NLLB models achieve higher automatic translation scores than the investigated LLM adaptation strategies. Based on these results, our final submission adopts a fine-tuned NLLB-based translation pipeline. We discuss the main observations from the different approaches explored during development. We release the code and models produced in these experiments through a publicly accessible GitHub repository https://github.com/schtailmuel/wmt26-lila/
Anthology ID:
2026.wmt-main.60
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:
1203–1212
Language:
URL:
https://aclanthology.org/2026.wmt-main.60/
DOI:
Bibkey:
Cite (ACL):
Mirelle Bueno, Lucas Domingues, Samuel Frontull, Jean Maillard, and Sushil Garg. 2026. LiLa at WMT 2026 General MT Task: Exploring Beyond NMT and Learning the Limits of LLM Adaptation for Ligurian and Ladin. In Proceedings of the Eleventh Conference on Machine Translation, pages 1203–1212, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
LiLa at WMT 2026 General MT Task: Exploring Beyond NMT and Learning the Limits of LLM Adaptation for Ligurian and Ladin (Bueno et al., WMT 2026)
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PDF:
https://aclanthology.org/2026.wmt-main.60.pdf