ACL 2025finding0 citations

Large Vocabulary Size Improves Large Language Models

Sho Takase, Ryokan Ri, Shun Kiyono, Takuya Kato

Abstract

This paper empirically investigates the relationship between subword vocabulary size and the performance of large language models (LLMs) to provide insights on how to define the vocabulary size. Experimental results show that larger vocabulary sizes lead to better performance in LLMs. Moreover, we consider a continual training scenario where a pre-trained language model is trained on a different target language. We introduce a simple method to use a new vocabulary instead of the pre-defined one. We show that using the new vocabulary outperforms the model with the vocabulary used in pre-training.

BibTeX
@inproceedings{takase-etal-2025-large,
    title = "Large Vocabulary Size Improves Large Language Models",
    author = "Takase, Sho  and
      Ri, Ryokan  and
      Kiyono, Shun  and
      Kato, Takuya",
    editor = "Che, Wanxiang  and
      Nabende, Joyce  and
      Shutova, Ekaterina  and
      Pilehvar, Mohammad Taher",
    booktitle = "Findings of the Association for Computational Linguistics: ACL 2025",
    month = jul,
    year = "2025",
    address = "Vienna, Austria",
    publisher = "Association for Computational Linguistics",
    url = "https://aclanthology.org/2025.findings-acl.57/",
    doi = "10.18653/v1/2025.findings-acl.57",
    pages = "1015--1026",
    ISBN = "979-8-89176-256-5"
}