MlingConf: A Comprehensive Study of Multilingual Confidence Estimation on Large Language Models

Boyang Xue, Hongru Wang, Rui Wang, Sheng Wang, Zezhong Wang, Yiming Du, Bin Liang, Wenxuan Zhang, Kam-Fai Wong


Abstract
The tendency of Large Language Models (LLMs) to generate hallucinations raises concerns regarding their reliability. Therefore, confidence estimations indicating the extent of trustworthiness of the generations become essential. However, current LLM confidence estimations in languages other than English remain underexplored. This paper addresses this gap by introducing a comprehensive investigation of Multilingual Confidence estimation (MlingConf) on LLMs, focusing on both language-agnostic (LA) and language-specific (LS) tasks to explore the performance and language dominance effects of multilingual confidence estimations on different tasks. The benchmark comprises four meticulously checked and human-evaluated high-quality multilingual datasets for LA tasks and one for the LS task tailored to specific social, cultural, and geographical contexts of a language. Our experiments reveal that on LA tasks English exhibits notable linguistic dominance in confidence estimations than other languages, while on LS tasks, using question-related language to prompt LLMs demonstrates better linguistic dominance in multilingual confidence estimations. The phenomena inspire a simple yet effective native-tone prompting strategy by employing language-specific prompts for LS tasks, effectively improving LLMs’ reliability and accuracy in LS scenarios.
Anthology ID:
2025.findings-acl.129
Volume:
Findings of the Association for Computational Linguistics: ACL 2025
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Wanxiang Che, Joyce Nabende, Ekaterina Shutova, Mohammad Taher Pilehvar
Venues:
Findings | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
2535–2556
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URL:
https://preview.aclanthology.org/ingestion-acl-25/2025.findings-acl.129/
DOI:
Bibkey:
Cite (ACL):
Boyang Xue, Hongru Wang, Rui Wang, Sheng Wang, Zezhong Wang, Yiming Du, Bin Liang, Wenxuan Zhang, and Kam-Fai Wong. 2025. MlingConf: A Comprehensive Study of Multilingual Confidence Estimation on Large Language Models. In Findings of the Association for Computational Linguistics: ACL 2025, pages 2535–2556, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
MlingConf: A Comprehensive Study of Multilingual Confidence Estimation on Large Language Models (Xue et al., Findings 2025)
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PDF:
https://preview.aclanthology.org/ingestion-acl-25/2025.findings-acl.129.pdf