NE-BERT: A Multilingual Language Model for Nine Northeast Indian Languages

Badal Nyalang


Abstract
Large pretrained language models have demonstrated remarkable capabilities across diverse languages, yet critically underrepresented low-resource languages remain marginalized. We present NE-BERT, a domain-specific multilingual encoder model trained on approximately 8.3 million sentences spanning 9 Northeast Indian languages and 2 anchor languages (Hindi, English), a linguistically diverse region with minimal representation in existing multilingual models. By employing weighted data sampling and a custom SentencePiece Unigram tokenizer, NE-BERT outperforms IndicBERT-V2 and MuRIL across all 9 Northeast Indian languages, achieving 15.97× and 7.64× lower average perplexity respectively, with 1.50× better tokenization fertility than mBERT. We address critical vocabulary fragmentation issues in extremely low-resource languages such as Pnar (1,002 sentences) and Kokborok (2,463 sentences) through aggressive upsampling strategies. Downstream evaluation on part-of-speech tagging validates practical utility on three Northeast Indian languages. We release NE-BERT, test sets, and training corpus under CC-BY-4.0 to support NLP research and digital inclusion for Northeast Indian communities.
Anthology ID:
2026.loreslm-1.1
Volume:
Proceedings of the Second Workshop on Language Models for Low-Resource Languages (LoResLM 2026)
Month:
March
Year:
2026
Address:
Rabat, Morocco
Editors:
Hansi Hettiarachchi, Tharindu Ranasinghe, Alistair Plum, Paul Rayson, Ruslan Mitkov, Mohamed Gaber, Damith Premasiri, Fiona Anting Tan, Lasitha Uyangodage
Venue:
LoResLM
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1–12
Language:
URL:
https://aclanthology.org/2026.loreslm-1.1/
DOI:
Bibkey:
Cite (ACL):
Badal Nyalang. 2026. NE-BERT: A Multilingual Language Model for Nine Northeast Indian Languages. In Proceedings of the Second Workshop on Language Models for Low-Resource Languages (LoResLM 2026), pages 1–12, Rabat, Morocco. Association for Computational Linguistics.
Cite (Informal):
NE-BERT: A Multilingual Language Model for Nine Northeast Indian Languages (Nyalang, LoResLM 2026)
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PDF:
https://aclanthology.org/2026.loreslm-1.1.pdf