Leveraging LLMs for Bangla Grammar Error Correction: Error Categorization, Synthetic Data, and Model Evaluation

Pramit Bhattacharyya, Arnab Bhattacharya


Abstract
Large Language Models (LLMs) perform exceedingly well in Natural Language Understanding (NLU) tasks for many languages including English. However, despite being the fifth most-spoken language globally, Grammatical Error Correction (GEC) in Bangla remains underdeveloped. In this work, we investigate how LLMs can be leveraged for improving Bangla GEC. For that, we first do an extensive categorization of 12 error classes in Bangla, and take a survey of native Bangla speakers to collect real-world errors. We next devise a rule-based noise injection method to create grammatically incorrect sentences corresponding to correct ones. The Vaiyākaraṇa dataset, thus created, consists of 5,67,422 sentences of which 2,27,119 are erroneous. This dataset is then used to instruction-tune LLMs for the task of GEC in Bangla. Evaluations show that instruction-tuning with Vaiyākaraṇa improves GEC performance of LLMs by 3-7 percentage points as compared to the zero-shot setting, and makes them achieve human-like performance in grammatical error identification. Humans, though, remain superior in error correction. The data and code are available from https://github.com/Bangla-iitk/Vaiyakarana.
Anthology ID:
2025.findings-acl.431
Volume:
Findings of the Association for Computational Linguistics: ACL 2025
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Wanxiang Che, Joyce Nabende, Ekaterina Shutova, Mohammad Taher Pilehvar
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Findings
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Publisher:
Association for Computational Linguistics
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Pages:
8220–8239
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URL:
https://preview.aclanthology.org/display_plenaries/2025.findings-acl.431/
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Cite (ACL):
Pramit Bhattacharyya and Arnab Bhattacharya. 2025. Leveraging LLMs for Bangla Grammar Error Correction: Error Categorization, Synthetic Data, and Model Evaluation. In Findings of the Association for Computational Linguistics: ACL 2025, pages 8220–8239, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
Leveraging LLMs for Bangla Grammar Error Correction: Error Categorization, Synthetic Data, and Model Evaluation (Bhattacharyya & Bhattacharya, Findings 2025)
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https://preview.aclanthology.org/display_plenaries/2025.findings-acl.431.pdf