Optimizing Multilingual BabyLM: The Roles of Tokenization, Data Packing, and Curriculum Learning

Fuming Yang, Kai-hao Yang, Hsuan Lien, Lukas Edman, Alexander Fraser


Abstract
Training multilingual language models under strict data constraints remains a challenging problem. This paper presents our submission to the BabyLM 2026 Multilingual Track, focusing on English, Dutch, and Chinese. Three key challenges arise under the BabyLM constraints: efficiently sharing limited model capacity, maximizing sequence utilization, and allocating parameters efficiently under a fixed vocabulary budget. To address these challenges, we propose a three-stage curriculum learning strategy that dynamically adjusts language mixing ratios throughout training. Furthermore, we investigate data packing strategies, comparing naive chunking with document wrapping to maximize the learning signal within a strict 100M-token budget. Finally, we design a custom BPE tokenizer with an asymmetric sampling strategy. By reducing the size of the embedding matrix, the saved parameters are reallocated to the Transformer backbone, enabling highly efficient GPT-2 and BERT models. Experimental results show that combining our curriculum strategy with document packing consistently improves GPT-2 training convergence and achieves highly competitive multilingual performance.
Anthology ID:
2026.babylm-main.47
Volume:
Proceedings of the Second BabyLM Workshop
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Leshem Choshen, Ryan Cotterell, Mustafa Omer Gul, Jaap Jumelet, Tal Linzen, Aaron Mueller, Suchir Salhan, Raj Sanjay Shah, Alex Warstadt, Ethan Gotlieb Wilcox
Venues:
BabyLM | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
598–610
Language:
URL:
https://aclanthology.org/2026.babylm-main.47/
DOI:
Bibkey:
Cite (ACL):
Fuming Yang, Kai-hao Yang, Hsuan Lien, Lukas Edman, and Alexander Fraser. 2026. Optimizing Multilingual BabyLM: The Roles of Tokenization, Data Packing, and Curriculum Learning. In Proceedings of the Second BabyLM Workshop, pages 598–610, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Optimizing Multilingual BabyLM: The Roles of Tokenization, Data Packing, and Curriculum Learning (Yang et al., BabyLM 2026)
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PDF:
https://aclanthology.org/2026.babylm-main.47.pdf