Linguistic Knowledge-Infused Fine-Tuning for Mitigating Gender Bias in Machine Translation

Luis Ernesto Garcia Estrada, Audrey Mash, Carlos Escolano, Maite Melero, Christine Basta


Abstract
Large Language Models (LLMs) achieve strong performance in machine translation (MT) but often encode gender bias, particularly when translating from non-gendered into gendered languages. This paper introduces a fine-tuning strategy to mitigate such bias in English-Spanish and English-Catalan translation. Using parameter-efficient LoRA fine-tuning, we apply linguistic knowledge infusion—a reasoning-based method that trains models to identify gendered referents and syntactic cues before generating translations. Experiments with Mistral–7B and Salamandrata–7B on MT-GenEval show that linguistically infused models improve gender accuracy by 15 percentage points and reduce gender gaps by 27 points in English-Spanish translation, with comparable trends for Catalan. Gains are strongest for Mistral, suggesting that explicit linguistic reasoning particularly benefits general-purpose LLMs. Overall, these results demonstrate that structured linguistic priors can enhance fairness and referential consistency in multilingual machine translation.
Anthology ID:
2026.lrec-main.685
Volume:
Proceedings of the Fifteenth Language Resources and Evaluation Conference
Month:
May
Year:
2026
Address:
Palma de Mallorca, Spain
Editors:
Stelios Piperidis, Núria Bel, Henk van den Heuvel, Nancy Ide, Simon Krek, Antonio Toral
Venue:
LREC
SIG:
Publisher:
ELRA Language Resource Association
Note:
Pages:
8699–8709
Language:
URL:
https://preview.aclanthology.org/ingest-lrec/2026.lrec-main.685/
DOI:
Bibkey:
Cite (ACL):
Luis Ernesto Garcia Estrada, Audrey Mash, Carlos Escolano, Maite Melero, and Christine Basta. 2026. Linguistic Knowledge-Infused Fine-Tuning for Mitigating Gender Bias in Machine Translation. International Conference on Language Resources and Evaluation, main:8699–8709.
Cite (Informal):
Linguistic Knowledge-Infused Fine-Tuning for Mitigating Gender Bias in Machine Translation (Garcia Estrada et al., LREC 2026)
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PDF:
https://preview.aclanthology.org/ingest-lrec/2026.lrec-main.685.pdf