One Model, Five Tasks, Two RTX 3090 GPUs: The HSE System for the Sorbian Track of WMT26 Multitask LLMs with Limited Resources

Michael Diskin


Abstract
We describe HSE’s submission to the Sorbian track of WMT26 Multitask LLMs with Lim- ited Resources, where a single 2B-parameter model must translate between German, Up- per Sorbian, and Lower Sorbian and also an- swer multiple-choice questions, check spelling and grammar, and solve maths problems in both Sorbian languages. Our system is one LoRA adapter on Qwen3.5-2B, trained on the official parallel data, synthetic spelling and grammar examples, a question-answering proxy, and English GSM8K in about nine GPU- hours on two consumer RTX 3090 GPUs. Ex- tended translation-only fine-tuning cost about ten points of question-answering accuracy, re- producing a WMT25 finding, and nearly erased the output conventions of the other tasks; the multitask mixture recovered them at almost no translation cost. The system ranked fourth of four teams. It far exceeded the baseline on translation (21.7 → 61.5 chrF++) and spell checking (6.7 → 63.6), but on grammar check- ing and maths reasoning it learned the answer format without the skill: the grammar score is almost exactly the share of error-free sentences, and maths accuracy did not exceed the baseline. Two negative results may transfer to other low- resource settings. Synthetic holdouts did not predict performance on the official tasks in ei- ther direction, and self-translated training prob- lems passed every automatic check yet changed meaning in at least 6 of 20 inspected cases. The model is publicly available.
Anthology ID:
2026.wmt-main.209
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:
2652–2661
Language:
URL:
https://aclanthology.org/2026.wmt-main.209/
DOI:
Bibkey:
Cite (ACL):
Michael Diskin. 2026. One Model, Five Tasks, Two RTX 3090 GPUs: The HSE System for the Sorbian Track of WMT26 Multitask LLMs with Limited Resources. In Proceedings of the Eleventh Conference on Machine Translation, pages 2652–2661, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
One Model, Five Tasks, Two RTX 3090 GPUs: The HSE System for the Sorbian Track of WMT26 Multitask LLMs with Limited Resources (Diskin, WMT 2026)
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https://aclanthology.org/2026.wmt-main.209.pdf