Low-Resource Transliteration for Roman-Urdu and Urdu Using Transformer-Based Models

Umer Butt, Stalin Varanasi, Günter Neumann


Abstract
As the Information Retrieval (IR) field increasingly recognizes the importance of inclusivity, addressing the needs of low-resource languages remains a significant challenge. Transliteration between Urdu and its Romanized form, Roman Urdu, remains underexplored despite the widespread use of both scripts in South Asia. Prior work using RNNs on the Roman-Urdu-Parl dataset showed promising results but suffered from poor domain adaptability and limited evaluation. We propose a transformer-based approach using the m2m100 multilingual translation model, enhanced with masked language modeling (MLM) pretraining and fine-tuning on both Roman-Urdu-Parl and the domain diverse Dakshina dataset. To address previous evaluation flaws, we introduce rigorous dataset splits and assess performance using BLEU, character-level BLEU, and CHRF. Our model achieves strong transliteration performance, with Char-BLEU scores of 96.37 for Urdu→Roman-Urdu and 97.44 for Roman-Urdu→Urdu. These results outperform both RNN baselines and GPT-4o Mini and demonstrate the effectiveness of multilingual transfer learning for low-resource transliteration tasks.
Anthology ID:
2025.loresmt-1.13
Volume:
Proceedings of the Eighth Workshop on Technologies for Machine Translation of Low-Resource Languages (LoResMT 2025)
Month:
May
Year:
2025
Address:
Albuquerque, New Mexico, U.S.A.
Editors:
Atul Kr. Ojha, Chao-hong Liu, Ekaterina Vylomova, Flammie Pirinen, Jonathan Washington, Nathaniel Oco, Xiaobing Zhao
Venues:
LoResMT | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
144–153
Language:
URL:
https://preview.aclanthology.org/fix-sig-urls/2025.loresmt-1.13/
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Bibkey:
Cite (ACL):
Umer Butt, Stalin Varanasi, and Günter Neumann. 2025. Low-Resource Transliteration for Roman-Urdu and Urdu Using Transformer-Based Models. In Proceedings of the Eighth Workshop on Technologies for Machine Translation of Low-Resource Languages (LoResMT 2025), pages 144–153, Albuquerque, New Mexico, U.S.A.. Association for Computational Linguistics.
Cite (Informal):
Low-Resource Transliteration for Roman-Urdu and Urdu Using Transformer-Based Models (Butt et al., LoResMT 2025)
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https://preview.aclanthology.org/fix-sig-urls/2025.loresmt-1.13.pdf