Source-primed Multi-turn Conversation Helps Large Language Models Translate Documents

Hanxu Hu, Jannis Vamvas, Rico Sennrich


Abstract
LLMs have paved the way for truly simple document-level machine translation, but challenges such as omission errors remain. In this paper, we study a simple method for handling document-level machine translation, by leveraging previous contexts in a multi-turn conversational manner. Specifically, by decomposing documents into segments and iteratively translating them while maintaining previous turns, this method ensures coherent translations without additional training, and can fully re-use the KV cache of previous turns thus minimizing computational overhead. We further propose a ‘source-primed’ method that first provides the whole source document before multi-turn translation. We empirically show this multi-turn method outperforms both translating entire documents in a single turn and translating each segment independently according to multiple automatic metrics in representative LLMs, establishing a strong baseline for document-level translation using LLMs.
Anthology ID:
2025.findings-emnlp.1289
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:
23702–23712
Language:
URL:
https://aclanthology.org/2025.findings-emnlp.1289/
DOI:
Bibkey:
Cite (ACL):
Hanxu Hu, Jannis Vamvas, and Rico Sennrich. 2025. Source-primed Multi-turn Conversation Helps Large Language Models Translate Documents. In Findings of the Association for Computational Linguistics: EMNLP 2025, pages 23702–23712, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
Source-primed Multi-turn Conversation Helps Large Language Models Translate Documents (Hu et al., Findings 2025)
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https://aclanthology.org/2025.findings-emnlp.1289.pdf
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