TREX: Tokenizer Regression for Optimal Data Mixture

Fuente: arXiv
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Main Authors: Won, Inho, Yoo, Hangyeol, Cho, Minkyung, Park, Jungyeul, Song, Hoyun, Lim, KyungTae
Format: Preprint
Published: 2026
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author Won, Inho
Yoo, Hangyeol
Cho, Minkyung
Park, Jungyeul
Song, Hoyun
Lim, KyungTae
author_facet Won, Inho
Yoo, Hangyeol
Cho, Minkyung
Park, Jungyeul
Song, Hoyun
Lim, KyungTae
contents Building effective tokenizers for multilingual Large Language Models (LLMs) requires careful control over language-specific data mixtures. While a tokenizer's compression performance critically affects the efficiency of LLM training and inference, existing approaches rely on heuristics or costly large-scale searches to determine optimal language ratios. We introduce Tokenizer Regression for Optimal Data MiXture (TREX), a regression-based framework that efficiently predicts the optimal data mixture for tokenizer training. TREX trains small-scale proxy tokenizers on random mixtures, gathers their compression statistics, and learns to predict compression performance from data mixtures. This learned model enables scalable mixture search before large-scale tokenizer training, mitigating the accuracy-cost trade-off in multilingual tokenizer design. Tokenizers trained with TReX's predicted mixtures outperform mixtures based on LLaMA3 and uniform distributions by up to 12% in both inand out-of-distribution compression efficiency, demonstrating strong scalability, robustness, and practical effectiveness.
format Preprint
id arxiv_https___arxiv_org_abs_2601_13588
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle TREX: Tokenizer Regression for Optimal Data Mixture
Won, Inho
Yoo, Hangyeol
Cho, Minkyung
Park, Jungyeul
Song, Hoyun
Lim, KyungTae
Computation and Language
Artificial Intelligence
68T50
I.2.7
Building effective tokenizers for multilingual Large Language Models (LLMs) requires careful control over language-specific data mixtures. While a tokenizer's compression performance critically affects the efficiency of LLM training and inference, existing approaches rely on heuristics or costly large-scale searches to determine optimal language ratios. We introduce Tokenizer Regression for Optimal Data MiXture (TREX), a regression-based framework that efficiently predicts the optimal data mixture for tokenizer training. TREX trains small-scale proxy tokenizers on random mixtures, gathers their compression statistics, and learns to predict compression performance from data mixtures. This learned model enables scalable mixture search before large-scale tokenizer training, mitigating the accuracy-cost trade-off in multilingual tokenizer design. Tokenizers trained with TReX's predicted mixtures outperform mixtures based on LLaMA3 and uniform distributions by up to 12% in both inand out-of-distribution compression efficiency, demonstrating strong scalability, robustness, and practical effectiveness.
title TREX: Tokenizer Regression for Optimal Data Mixture
topic Computation and Language
Artificial Intelligence
68T50
I.2.7
url https://arxiv.org/abs/2601.13588