Thunder-Tok: Minimizing Tokens per Word in Tokenizing Korean Texts for Generative Language Models

Gyeongje Cho, Yeonkyoun So, Chanwoo Park, Sangmin Lee, Sungmok Jung +1 more
6/18/2025
cs.CLcs.AI

No confident code implementation found for this paper. 2 possible matches can be shown below.

Abstract

This paper introduces Thunder-Tok, a new Korean tokenizer designed to reduce token fertility without compromising model performance. Our approach uses a rule-based pre-tokenization method that aligns with the linguistic structure of the Korean language. We also create a seed vocabulary containing tokens that resemble linguistic units and employ a branching entropy-based selection algorithm. These techniques increase the average token length, thus lowering fertility while preserving linguistic information. Experimental results indicate that Thunder-Tok reduces fertility by approximately 10% (i.e., reduces the number of tokens by 10%, improving the inference speed by 10%) compared to BPE without compromising performance across various downstream tasks. These findings demonstrate that our linguistically informed approach is effective and practical for designing efficient tokenizers for language models.

View on arXivView PDF

Code Implementations

No confident code match yet

We couldn't find an author-owned or strongly-evidenced community implementation for this paper. 2 weaker matches are hidden by default — verify before relying on them.

No code implementations found yet.

Know of an implementation? Let us know in the comments below!

Similar Papers

Cite this paper

@article{cho2025thundertok,
  title  = {Thunder-Tok: Minimizing Tokens per Word in Tokenizing Korean Texts for Generative Language Models},
  author = {Gyeongje Cho and Yeonkyoun So and Chanwoo Park and Sangmin Lee and Sungmok Jung and Jaejin Lee},
  year   = {2025},
  eprint = {2506.15138},
  archivePrefix = {arXiv},
  url    = {http://arxiv.org/abs/2506.15138v1}
}

Add a badge to your README

Shows whether official code is linked for this paper.

Code of Paper badge
[![Code of Paper](https://codeofpaper.com/badge/2506.15138.svg)](https://codeofpaper.com/paper/2506.15138)

Discussion