# Qwenfant: Train Big Character-level BabyLMs on Concise Parallel Text

arXiv: https://arxiv.org/abs/2610.19294 · HTML: https://mlsanity.com/paper/2610.19294/

## Key facts

- No citing papers in the map yet (data through 14 Oct 2026).
- Builds on 14 of its 24 references that are in the map.
- First posted on arXiv 13 Oct 2026.

## Builds on (most cited first, 14 of 14)

- [BERT: Pre-training of Deep Bidirectional Transformers for Language Understanding](https://mlsanity.com/paper/1810.04805/) (2018)
- [RoFormer: Enhanced Transformer with Rotary Position Embedding](https://mlsanity.com/paper/2104.09864/) (2021)
- [ByT5: Towards a token-free future with pre-trained byte-to-byte models](https://mlsanity.com/paper/2105.13626/) (2021)
- [TinyStories: How Small Can Language Models Be and Still Speak Coherent English?](https://mlsanity.com/paper/2305.07759/) (2023)
- [Byte Latent Transformer: Patches Scale Better Than Tokens](https://mlsanity.com/paper/2412.09871/) (2024)
- [Demystifying Synthetic Data in LLM Pre-training: A Systematic Study of Scaling Laws, Benefits, and Pitfalls](https://mlsanity.com/paper/2510.01631/) (2025)
- [Hyperparameter Transfer Enables Consistent Gains of Matrix-Preconditioned Optimizers Across Scales](https://mlsanity.com/paper/2512.05620/) (2025)
- [Are Character-level Translations Worth the Wait? Comparing ByT5 and mT5 for Machine Translation](https://mlsanity.com/paper/2302.14220/) (2023)
- [Dialogue Is Not Enough to Make a Communicative BabyLM (But Neither Is Developmentally Inspired Reinforcement Learning)](https://mlsanity.com/paper/2510.20358/) (2025)
- [Too Much Information: Keeping Training Simple for BabyLMs](https://mlsanity.com/paper/2311.01955/) (2023)
- [BERTtime Stories: Investigating the Role of Synthetic Story Data in Language Pre-training](https://mlsanity.com/paper/2410.15365/) (2024)
- [Dreaming Out Loud: A Self-Synthesis Approach For Training Vision-Language Models With Developmentally Plausible Data](https://mlsanity.com/paper/2411.00828/) (2024)
- [Mask and You Shall Receive: Optimizing Masked Language Modeling For Pretraining BabyLMs](https://mlsanity.com/paper/2510.20475/) (2025)
- [Contrastive Decoding for Synthetic Data Generation in Low-Resource Language Modeling](https://mlsanity.com/paper/2510.08245/) (2025)

## Abstract (arXiv)

This work concerns our submission for the Multilingual track of the 2026 BabyLM Challenge. We improve on our baseline using data that has been summarized and translated by an LLM, showing that higher-quality data can come from synthetic sources. We further improve with 2 simple changes: using a larger model, and using a character-level vocabulary. Both of these changes require LoRA-style fine-tuning for realizing their full potential. We dub our final Qwen3-based model Qwenfant, which, at the time of submission, ranks 1st in the Multilingual track.