PEGRL: Improving Machine Translation by Post-Editing Guided Reinforcement Learning

Fuente: arXiv
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Main Authors: Shen, Yunzhi, Zhou, Hao, Huang, Xin, Han, Xue, Feng, Junlan, Huang, Shujian
Format: Preprint
Published: 2026
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author Shen, Yunzhi
Zhou, Hao
Huang, Xin
Han, Xue
Feng, Junlan
Huang, Shujian
author_facet Shen, Yunzhi
Zhou, Hao
Huang, Xin
Han, Xue
Feng, Junlan
Huang, Shujian
contents Reinforcement learning (RL) has shown strong promise for LLM-based machine translation, with recent methods such as GRPO demonstrating notable gains; nevertheless, translation-oriented RL remains challenged by noisy learning signals arising from Monte Carlo return estimation, as well as a large trajectory space that favors global exploration over fine-grained local optimization. We introduce \textbf{PEGRL}, a \textit{two-stage} RL framework that uses post-editing as an auxiliary task to stabilize training and guide overall optimization. At each iteration, translation outputs are sampled to construct post-editing inputs, allowing return estimation in the post-editing stage to benefit from conditioning on the current translation behavior, while jointly supporting both global exploration and fine-grained local optimization. A task-specific weighting scheme further balances the contributions of translation and post-editing objectives, yielding a biased yet more sample-efficient estimator. Experiments on English$\to$Finnish, English$\to$Turkish, and English$\leftrightarrow$Chinese show consistent gains over RL baselines, and for English$\to$Turkish, performance on COMET-KIWI is comparable to advanced LLM-based systems (DeepSeek-V3.2). Our code and a set of representative pretrained models are publicly available at \url{https://github.com/NJUNLP/peg-rl} and \url{https://huggingface.co/collections/DGME/pegrl}
format Preprint
id arxiv_https___arxiv_org_abs_2602_03352
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle PEGRL: Improving Machine Translation by Post-Editing Guided Reinforcement Learning
Shen, Yunzhi
Zhou, Hao
Huang, Xin
Han, Xue
Feng, Junlan
Huang, Shujian
Computation and Language
Reinforcement learning (RL) has shown strong promise for LLM-based machine translation, with recent methods such as GRPO demonstrating notable gains; nevertheless, translation-oriented RL remains challenged by noisy learning signals arising from Monte Carlo return estimation, as well as a large trajectory space that favors global exploration over fine-grained local optimization. We introduce \textbf{PEGRL}, a \textit{two-stage} RL framework that uses post-editing as an auxiliary task to stabilize training and guide overall optimization. At each iteration, translation outputs are sampled to construct post-editing inputs, allowing return estimation in the post-editing stage to benefit from conditioning on the current translation behavior, while jointly supporting both global exploration and fine-grained local optimization. A task-specific weighting scheme further balances the contributions of translation and post-editing objectives, yielding a biased yet more sample-efficient estimator. Experiments on English$\to$Finnish, English$\to$Turkish, and English$\leftrightarrow$Chinese show consistent gains over RL baselines, and for English$\to$Turkish, performance on COMET-KIWI is comparable to advanced LLM-based systems (DeepSeek-V3.2). Our code and a set of representative pretrained models are publicly available at \url{https://github.com/NJUNLP/peg-rl} and \url{https://huggingface.co/collections/DGME/pegrl}
title PEGRL: Improving Machine Translation by Post-Editing Guided Reinforcement Learning
topic Computation and Language
url https://arxiv.org/abs/2602.03352