mmBERT Training Data (Ready-to-Use)

Complete Training Dataset: Pre-randomized and ready-to-use multilingual training data (3T tokens) for encoder model pre-training.

This dataset is part of the complete, pre-shuffled training data used to train the mmBERT encoder models. Unlike the individual phase datasets, this version is ready for immediate use but the mixture cannot be modified easily. The data is provided in decompressed MDS format ready for use with ModernBERT's Composer and the ModernBERT training repository.

Licensing & Attribution

This dataset aggregates multiple open-source datasets under permissive licenses. See individual source datasets for specific attribution requirements.

Related Resources

Models: mmBERT Model Suite
Individual Phases: Pre-training | Mid-training | Decay
Checkpoints: Training Checkpoints
Paper: Arxiv link
Code: GitHub Repository

Citation

@misc{marone2025mmbertmodernmultilingualencoder,
      title={mmBERT: A Modern Multilingual Encoder with Annealed Language Learning}, 
      author={Marc Marone and Orion Weller and William Fleshman and Eugene Yang and Dawn Lawrie and Benjamin Van Durme},
      year={2025},
      eprint={2509.06888},
      archivePrefix={arXiv},
      primaryClass={cs.CL},
      url={https://arxiv.org/abs/2509.06888}, 
}