Publication Type
Conference Proceeding Article
Version
publishedVersion
Publication Date
8-2025
Abstract
Large language models (LLMs) have become increasingly central to AI applications worldwide, necessitating robust multilingual safety alignment to ensure secure deployment across diverse linguistic contexts. Existing preference learning methods for safety alignment, such as RLHF and DPO, are primarily monolingual and struggle with noisy multilingual data. To address these limitations, we introduce Multilingual reward gaP Optimization (MPO), a novel approach that leverages the well-aligned safety capabilities of the dominant language (e.g., English) to improve safety alignment across multiple languages. MPO directly minimizes the reward gap difference between the dominant language and target languages, effectively transferring safety capabilities while preserving the original strengths of the dominant language. Extensive experiments on three LLMs, LLaMA-3.1, Gemma-2 and Qwen2.5, validate MPO’s efficacy in multilingual safety alignment without degrading general multilingual utility.
Discipline
Artificial Intelligence and Robotics | Programming Languages and Compilers
Research Areas
Intelligent Systems and Optimization
Areas of Excellence
Digital transformation
Publication
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics, Vienna, Austria, 2025 July 27 - August 1
First Page
23564
Last Page
23587
Identifier
10.18653/v1/2025.acl-long.1149
Publisher
Association for Computational Linguistics
City or Country
USA
Citation
ZHAO, Weixiang; HU, Yulin; DENG, Yang; WU, Tongtong; ZHANG, Wenxuan; GUO, Jiahe; ZHANG, An; ZHAO, Yanyan; QIN, Bing; CHUA, Tat-Seng; and LIU, Ting.
MPO: Multilingual safety alignment via reward gap optimization. (2025). Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics, Vienna, Austria, 2025 July 27 - August 1. 23564-23587.
Available at: https://ink.library.smu.edu.sg/sis_research/10378
Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Additional URL
https://doi.org/10.18653/v1/2025.acl-long.1149
Included in
Artificial Intelligence and Robotics Commons, Programming Languages and Compilers Commons