DELAB-IIITM WMT25: Enhancing Low-Resource Machine Translation for Manipuri and Assamese

Dingku Oinam, Navanath Saharia


Abstract
This paper describe DELAB-IIITM’s submission system for the WMT25 machine translation shared task. We participated in two sub-task of the Indic Translation Task, en↔as and en↔mn i.e. Assamese (Indo Aryan language) and Manipuri (Tibeto Burman language) with a total of six translation directions, including mn→en, mn←en, en→as, en←as, mn→as, mn←as. Our fine tuning process aims to leverages the pretrained multilingual NLLB-200 model, a machine translation model developed by Meta AI as part of the No Language Left Behind (NLLB) project, through two main development, Synthetic parallel corpus creation and Strategic Fine-tuning. The Fine-tuning process involves strict data cleaning protocols, Adafactor optimizer with low learning rate(2e-5), 2 training epochs, train-test data splits to prevent overfitting, and Seq2SeqTrainer framework. The official test data was used to generate the target language with our fine-tuned model. Experimental results show that our method improves the BLEU scores for translation of these two language pairs. These findings confirm that back-translation remains challenging, largely due to morphological complexity and limited data availability.
Anthology ID:
2025.wmt-1.98
Volume:
Proceedings of the Tenth Conference on Machine Translation
Month:
November
Year:
2025
Address:
Suzhou, China
Editors:
Barry Haddow, Tom Kocmi, Philipp Koehn, Christof Monz
Venue:
WMT
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1222–1226
Language:
URL:
https://aclanthology.org/2025.wmt-1.98/
DOI:
Bibkey:
Cite (ACL):
Dingku Oinam and Navanath Saharia. 2025. DELAB-IIITM WMT25: Enhancing Low-Resource Machine Translation for Manipuri and Assamese. In Proceedings of the Tenth Conference on Machine Translation, pages 1222–1226, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
DELAB-IIITM WMT25: Enhancing Low-Resource Machine Translation for Manipuri and Assamese (Oinam & Saharia, WMT 2025)
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https://aclanthology.org/2025.wmt-1.98.pdf