TopXGen: Topic-Diverse Parallel Data Generation for Low-Resource Machine Translation

Armel Randy Zebaze, Benoît Sagot, Rachel Bawden


Abstract
LLMs have been shown to perform well in machine translation (MT) with the use of in-context learning, rivalling supervised models when translating into high-resource languages (HRLs). However, they lag behind when dealing with low-resource language (LRLs). Example selection via similarity search and supervised fine-tuning help. However the improvements they give are limited by the size, quality and diversity of existing parallel datasets. A common technique in low-resource MT is synthetic parallel data creation, the most frequent of which is backtranslation, whereby existing target-side texts are automatically translated into the source language. However, it also relies on the existence of good quality and relevant target-side texts, which are not readily available for many LRLs. In this paper, we present a new approach, TopXGen, which involves using an LLM to automatically generate topic-specific target-side data in the LRL, which can then be backtranslated to produce useful and diverse parallel texts for ICL and fine-tuning. Our intuition is that while LLMs struggle to translate into LRLs, their ability to translate well into HRLs and their multilinguality enable them to generate good quality, natural-sounding target-side texts, which can be translated well into a high-resource source language. We show that TopXGen boosts LLM translation performance during fine-tuning and in-context learning. Our code and outputs will be made freely available.
Anthology ID:
2025.findings-emnlp.1217
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:
22358–22381
Language:
URL:
https://preview.aclanthology.org/name-variant-enfa-fane/2025.findings-emnlp.1217/
DOI:
10.18653/v1/2025.findings-emnlp.1217
Bibkey:
Cite (ACL):
Armel Randy Zebaze, Benoît Sagot, and Rachel Bawden. 2025. TopXGen: Topic-Diverse Parallel Data Generation for Low-Resource Machine Translation. In Findings of the Association for Computational Linguistics: EMNLP 2025, pages 22358–22381, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
TopXGen: Topic-Diverse Parallel Data Generation for Low-Resource Machine Translation (Zebaze et al., Findings 2025)
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PDF:
https://preview.aclanthology.org/name-variant-enfa-fane/2025.findings-emnlp.1217.pdf
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 2025.findings-emnlp.1217.checklist.pdf