SMUGRI-COPA: Evaluating Commonsense Reasoning for Low-Resource Finnic Languages

Taido Purason, Marili Tomingas, Janek Vaab, Mark Fishel


Abstract
We introduce SMUGRI-COPA, a commonsense reasoning benchmark for two heavily under-resourced Finnic languages: Võro and Livonian. Existing evaluation resources for these languages rely on a translated subset of FLORES sentences, limiting linguistic diversity and the evaluation of broader language understanding. To address this gap, we human-translate the COPA (Choice of Plausible Alternatives) benchmark into Võro and Livonian, creating, to our knowledge, the largest discriminative benchmark currently available for these languages. We evaluate a wide range of proprietary and open-weight language models on SMUGRI-COPA and compare the results with Estonian XCOPA. Our results reveal a substantial performance gap between Estonian and the lower-resource languages, with most models failing to significantly outperform random guessing on Livonian. We further find that enabling reasoning for GPT-5 substantially improves accuracy for Võro and Livonian, while its reasoning summaries show frequent reliance on explicit translation of the tasks. Our work highlights the challenges of evaluating endangered language understanding and provides a new resource for multilingual evaluation research.
Anthology ID:
2026.findings-emnlp.2080
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
44289–44303
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.2080/
DOI:
Bibkey:
Cite (ACL):
Taido Purason, Marili Tomingas, Janek Vaab, and Mark Fishel. 2026. SMUGRI-COPA: Evaluating Commonsense Reasoning for Low-Resource Finnic Languages. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 44289–44303, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
SMUGRI-COPA: Evaluating Commonsense Reasoning for Low-Resource Finnic Languages (Purason et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.2080.pdf