How Well Does Mathematical Reasoning Transfer Across Languages in English-Centric LLMs?

Wen Yang, Junhong Wu, Chong Li, Chengqing Zong, Jiajun Zhang


Abstract
Recent advances in Reinforcement Post-Training (RPT) have substantially improved the mathematical reasoning capabilities of large language models (LLMs), but it remains unclear how well such gains transfer across languages. In this work, we study cross-lingual mathematical reasoning transfer in English-centric LLMs under controlled multilingual evaluation. We first evaluate a range of English-centric reasoning models on multilingual mathematical reasoning benchmarks and find that transfer is highly variable across initial model choice, target language, and training paradigm. Through controlled comparative experiments, we further find that stronger English-centric initialization does not necessarily lead to stronger relative transfer efficiency, even when it yields higher multilingual reasoning accuracy. Finally, we show that the largest improvement comes from moving beyond English-only supervision: adding a single parallel language yields a substantial gain, while further gains from additional languages are smaller but consistent. Overall, our results highlight the need to evaluate multilingual mathematical reasoning directly, using both absolute performance and relative transfer-efficiency metrics.
Anthology ID:
2026.emnlp-main.999
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
22983–23009
Language:
URL:
https://aclanthology.org/2026.emnlp-main.999/
DOI:
Bibkey:
Cite (ACL):
Wen Yang, Junhong Wu, Chong Li, Chengqing Zong, and Jiajun Zhang. 2026. How Well Does Mathematical Reasoning Transfer Across Languages in English-Centric LLMs?. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 22983–23009, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
How Well Does Mathematical Reasoning Transfer Across Languages in English-Centric LLMs? (Yang et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.999.pdf