Disentangling Language Understanding and Reasoning Structures in Cross-lingual Chain-of-Thought Prompting
Khanh-Tung Tran, Nguyet-Hang Vu, Barry O’Sullivan, Hoang D. Nguyen
Abstract
Cross-lingual chain-of-thought prompting techniques have proven effective for investigating diverse reasoning paths in Large Language Models (LLMs), especially for low-resource languages. Despite these empirical gains, the mechanisms underlying cross-lingual improvements remain perplexing. This study, therefore, addresses whether the benefits of cross-lingual prompting arise from language-specific reasoning structures intrinsic to each language, or are simply a consequence of improved comprehension through cross-linguistic exposure. We employ neuron intervention and perturbation techniques to analyze and deactivate language-specific reasoning neurons during cross-lingual prompting, leading to performance disparities across languages, up to 27.4%. Our findings disentangle that these neurons are essential for reasoning in their respective languages, but have minimal effect on reasoning in other languages, providing evidence for the existence of language-specific local reasoning structures and guiding the development of more interpretable and effective multilingual AI systems.- Anthology ID:
- 2025.findings-emnlp.652
- Volume:
- Findings of the Association for Computational Linguistics: EMNLP 2025
- Month:
- November
- Year:
- 2025
- Address:
- Suzhou, China
- Editors:
- Christos Christodoulopoulos, Tanmoy Chakraborty, Carolyn Rose, Violet Peng
- Venue:
- Findings
- SIG:
- Publisher:
- Association for Computational Linguistics
- Note:
- Pages:
- 12200–12206
- Language:
- URL:
- https://preview.aclanthology.org/author-page-yu-wang-polytechnic/2025.findings-emnlp.652/
- DOI:
- 10.18653/v1/2025.findings-emnlp.652
- Cite (ACL):
- Khanh-Tung Tran, Nguyet-Hang Vu, Barry O’Sullivan, and Hoang D. Nguyen. 2025. Disentangling Language Understanding and Reasoning Structures in Cross-lingual Chain-of-Thought Prompting. In Findings of the Association for Computational Linguistics: EMNLP 2025, pages 12200–12206, Suzhou, China. Association for Computational Linguistics.
- Cite (Informal):
- Disentangling Language Understanding and Reasoning Structures in Cross-lingual Chain-of-Thought Prompting (Tran et al., Findings 2025)
- PDF:
- https://preview.aclanthology.org/author-page-yu-wang-polytechnic/2025.findings-emnlp.652.pdf