What Does Post-Training Change in Multilingual Reasoning?

arXiv:2609.37104 · cs.CL, cs.AI · Submitted 2026-09-29 · Read on arXiv

cs.CL, cs.AI

Submitted: 2026-09-29

Updated: 2026-09-29

Comments: 20 pages, 9 figures, 21 tables. Main paper and supplementary material in one document

License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Terminology

• Trace — 71× in this paper · explained in 2 episodes
• Accuracy — 29× in this paper · explained in 1 episode
• Fine-Tuning — 9× in this paper · explained in 5 episodes
• Fidelity — 8× in this paper · explained in 2 episodes
• Reinforcement Learning — 8× in this paper · explained in 4 episodes
• Robustness — 4× in this paper · explained in 5 episodes
• Benchmark — 3× in this paper · explained in 2 episodes
• Consistency — 3× in this paper · explained in 3 episodes
• Failure Modes — 3× in this paper · explained in 3 episodes
• Ablation — 2× in this paper · explained in 1 episode
• LLM judge — 2× in this paper · explained in 2 episodes
• Reasoning Traces — 2× in this paper · explained in 3 episodes
• Supervised Fine-Tuning (SFT) — 2× in this paper · explained in 8 episodes
• Tokenization — 2× in this paper · explained in 2 episodes
• Actor — 1× in this paper · explained in 3 episodes
• Aggregation — 1× in this paper · explained in 1 episode
• Alignment — 1× in this paper · explained in 1 episode
• Representation Learning — 1× in this paper · explained in 2 episodes
• Systematic Bias — 1× in this paper · explained in 3 episodes
• Transformer — 1× in this paper · explained in 2 episodes

Sources

• Cross-lingual Self-Consistency for Multilingual Reasoning with Language Models
• ReasonXL: A Large-Scale Corpus for Language-Specific Reasoning in LLMs
• Learn Globally, Speak Locally: Bridging the Gaps in Multilingual Reasoning
• Proximal Policy Optimization Algorithms
• Do Multilingual LLMs Think In English?
• Language Matters: How Do Multilingual Input and Reasoning Paths Affect Large Reasoning Models?
• Qwen3 Technical Report
• Disentangling Language Roles in Multilingual LLM Task Execution
• Hunyuan-MT Technical Report

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