Language-Aware Token Boosting: LLM Language Confusion Reduction Without Tuning

Trapoom Ukarapol, Pakhapoom Sarapat, Nut Chukamphaeng


Abstract
Large language models (LLMs) sometimes exhibit language confusion when generating non-English text. Existing approaches typically rely on fine-tuning to mitigate this issue. In contrast, we propose a tuning-free paradigm for reducing language confusion. Within this paradigm, we introduce two methods: Language-Aware Token Boosting (LATB), which applies targeted perturbations to tokens associated with the desired language, and Adaptive Language-Aware Token Boosting (Adaptive-LATB), which dynamically adjusts these perturbations based on the model’s confidence in the intended language. Experiments demonstrate that our methods effectively improve multilingual alignment by reducing language confusion, while maintain the summarization quality without requiring any additional fine-tuning. Our code is publicly available.[<https://github.com/scbdatax/genai-datax-language-aware-token-boosting>].
Anthology ID:
2026.acl-short.40
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
ACL
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Publisher:
Association for Computational Linguistics
Note:
Pages:
481–489
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URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-short.40/
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Cite (ACL):
Trapoom Ukarapol, Pakhapoom Sarapat, and Nut Chukamphaeng. 2026. Language-Aware Token Boosting: LLM Language Confusion Reduction Without Tuning. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers), pages 481–489, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Language-Aware Token Boosting: LLM Language Confusion Reduction Without Tuning (Ukarapol et al., ACL 2026)
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https://preview.aclanthology.org/ingest-acl/2026.acl-short.40.pdf
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