Alligators All Around: Mitigating Lexical Confusion in Low-resource Machine Translation

Elizabeth Nielsen, Isaac Rayburn Caswell, Jiaming Luo, Colin Cherry


Abstract
Current machine translation (MT) systems for low-resource languages have a particular failure mode: When translating words in a given domain, they tend to confuse words within that domain. So, for example, “lion” might be translated as “alligator”, and “orange” might be rendered as “purple.” We propose a recall-based metric for measuring this problem and show that the problem exists in 122 low-resource languages. We then show that this problem can be mitigated by using a large language model (LLM) to post-edit the MT output, specifically by including the entire GATITOS lexicon for the relevant language as a very long context prompt. We show gains in average ChrF score over the set of 122 languages, and we show that the recall score for relevant lexical items also improves. Finally, we demonstrate that a small dedicated MT system with a general-purpose LLM as a post-editor is outperforms a lexicon-based RAG-LLM translator, suggesting a new paradigm for LLM use.
Anthology ID:
2025.naacl-short.18
Volume:
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 2: Short Papers)
Month:
April
Year:
2025
Address:
Albuquerque, New Mexico
Editors:
Luis Chiruzzo, Alan Ritter, Lu Wang
Venue:
NAACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
206–221
Language:
URL:
https://preview.aclanthology.org/fix-sig-urls/2025.naacl-short.18/
DOI:
Bibkey:
Cite (ACL):
Elizabeth Nielsen, Isaac Rayburn Caswell, Jiaming Luo, and Colin Cherry. 2025. Alligators All Around: Mitigating Lexical Confusion in Low-resource Machine Translation. In Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 2: Short Papers), pages 206–221, Albuquerque, New Mexico. Association for Computational Linguistics.
Cite (Informal):
Alligators All Around: Mitigating Lexical Confusion in Low-resource Machine Translation (Nielsen et al., NAACL 2025)
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PDF:
https://preview.aclanthology.org/fix-sig-urls/2025.naacl-short.18.pdf