TopXGen: Topic-Diverse Parallel Data Generation for Low-Resource Machine
  Translation
Authors: name: Armel Zebaze; name: Benoît Sagot; name: Rachel Bawden
Published: 2025-08-12 06:58:02

Abstract: LLMs have been shown to perform well in machine translation (MT) with the use
of in-context learning (ICL), rivaling supervised models when translating into
high-resource languages (HRLs). However, they lag behind when translating into
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, this assumes the
existence of good quality and relevant target-side texts, which are not readily
available for many LRLs. In this paper, we present TopXGen, an
LLM-based approach for the generation of high quality and topic-diverse data in
multiple LRLs, 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. Code and outputs are available at
https://github.com/ArmelRandy/topxgen.