MaiBERT: A Pre-training Corpus and Language Model for Low-Resourced Maithili Language
Paper · 2026 · Sumit Yadav, Raju Kumar Yadav, Utsav Maskey et al.
Summary
Maithili, an Indo-Aryan language spoken by millions in Nepal's Terai and in Bihar, has almost no pretrained models or standard datasets. Models built for Hindi or Nepali transfer imperfectly because Maithili has its own vocabulary and morphology. The authors assemble a Maithili pretraining corpus of roughly 18 million words (over 450MB after cleaning) from Wikipedia, OCR-digitised books and online news outlets. They use it to train maiBERT, a BERT-base-sized encoder (about 110M parameters) trained with a masked language modelling objective and a 30,000-token SentencePiece-BPE vocabulary. For evaluation, they build a ten-class Maithili news classification dataset labelled by native speakers and linguists. Fine-tuned maiBERT reaches 87.02% accuracy. This is only slightly above HindiBERT (86.89%), but maiBERT also beats NepBERTa, mBERT and MuRIL, and the authors report 5–7% gains on categories where Maithili-specific language matters most. Classical machine-learning baselines trail by about ten points. The model and data are released on Hugging Face as a foundation for further Maithili NLP work, such as NER or sentiment analysis.
Key points
- Pretraining corpus: about 18M words in 1,028,017 sentences, with 1,357,081 unique tokens. Sources are Maithili Wikipedia (~880K words), 418 scanned books processed with Tesseract OCR (~10.4M) and news sites such as Esamaad and Maithilijindabad (~6.6M).
- Model setup: TensorFlow BERT with 768-dimensional embeddings and sequences of up to 512 tokens. Training ran for 1,000,000 steps with batch size 64 and learning rate 5×10⁻⁵. The paper reports 4.6 GB memory use and 0.85 hours of compute time.
- Classification dataset: ten news categories, with Culture, Literature and Politics the largest. It was annotated by 3 native speakers and 2 experts (Cohen's Kappa 0.82) and split 70/15/15. The text gives 11,959 instances, but Table 1 totals 12,383.
- Results: maiBERT scores 87.02% versus HindiBERT's 86.89%, a gap of only 0.13 points. Among classical baselines, the best is linear SVM at 76.70%, and a simple neural network reaches 72.62%.
- Resources: the model is available as
rockerritesh/maiBERT_TFand the data asrockerritesh/maithiliNewsDataon Hugging Face.
Institutions
Fields, topics and concepts
📚 Shelves 4The field of science this work belongs to (OpenAlex fields).Computer Science · 16,667 worksArtificial Intelligence · 16,194 worksArts and Humanities · 16,039 worksLanguage and Linguistics · 15,891 works
🧭 Topics 2Research subjects and languages the work is about.Language models & pretraining · 3,320 worksLow-resource languages · 267 works
Cite
Cite as Sumit Yadav, Raju Kumar Yadav, Utsav Maskey, Gautam Siddharth Kashyap, Ganesh Gautam and Usman Naseem. 2026. MaiBERT: A Pre-training Corpus and Language Model for Low-Resourced Maithili Language. Proceedings of the Second Workshop on Language Models for Low-Resource Languages (LoResLM 2026).
@inproceedings{yadav2026maibert,
title = {{MaiBERT: A Pre-training Corpus and Language Model for Low-Resourced Maithili Language}},
author = {Sumit Yadav, Raju Kumar Yadav, Utsav Maskey, Gautam Siddharth Kashyap, Ganesh Gautam and Usman Naseem},
booktitle = {Proceedings of the Second Workshop on Language Models for Low-Resource Languages (LoResLM 2026)},
year = {2026},
doi = {10.18653/v1/2026.loreslm-1.38},
url = {https://doi.org/10.18653/v1/2026.loreslm-1.38}
}References
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