← Search

Tatsuya Hiraoka

10 accepted papers

2026

Beyond Perplexity: UTF-8 Validity in Byte-aware Language Models

ICML 2026poster

Byte-level tokenization enables language models to handle any Unicode input, but models can generate invalid UTF-8 sequences when encountering rare or unseen characters. We investigate the relationship between training scale and UTF-8 generation reliability with a 355M parameter model trained on 80B…

Cited by 0SourceScholar
2025

Investigating Neurons and Heads in Transformer-based LLMs for Typographical Errors

EMNLP 2025

This paper investigates how LLMs encode inputs with typos. We hypothesize that specific neurons and attention heads recognize typos and fix them internally using local and global contexts. We introduce a method to identify typo neurons and typo heads that work actively when inputs contain typos. Our

Cited by 0SourcePDFScholar
2025

Library-Like Behavior In Language Models is Enhanced by Self-Referencing Causal Cycles

ACL 2025long

We introduce the concept of the self-referencing causal cycle (abbreviated ReCall )—a mechanism that enables large language models (LLMs) to bypass the limitations of unidirectional causality, which underlies a phenomenon known as the reversal curse. When an LLM is prompted with sequential data, it…

2025

Spelling-out is not Straightforward: LLMs’ Capability of Tokenization from Token to Characters

EMNLP 2025

Large language models (LLMs) can spell out tokens character by character with high accuracy, yet they struggle with more complex character-level tasks, such as identifying compositional subcomponents within tokens. In this work, we investigate how LLMs internally represent and utilize character-leve

2025

SubRegWeigh: Effective and Efficient Annotation Weighing with Subword Regularization

COLING 2025main

NLP datasets may still contain annotation errors, even when they are manually annotated. Researchers have attempted to develop methods to automatically reduce the adverse effect of errors in datasets. However, existing methods are time-consuming because they require many trained models to detect err…

2025

The Geometry of Numerical Reasoning: Language Models Compare Numeric Properties in Linear Subspaces

NAACL 2025short

This paper investigates whether large language models (LLMs) utilize numerical attributes encoded in a low-dimensional subspace of theembedding space when answering questions involving numeric comparisons, e.g., Was Cristiano born before Messi? We first identified,using partial least squares regress…

Cited by 1SourcePDFScholar
2022

Single Model Ensemble for Subword Regularized Models in Low-Resource Machine Translation

ACL 2022findings

Subword regularizations use multiple subword segmentations during training to improve the robustness of neural machine translation models. In previous subword regularizations, we use multiple segmentations in the training process but use only one segmentation in the inference. In this study, we prop…

2022

Word-level Perturbation Considering Word Length and Compositional Subwords

ACL 2022findings

We present two simple modifications for word-level perturbation: Word Replacement considering Length (WR-L) and Compositional Word Replacement (CWR).In conventional word replacement, a word in an input is replaced with a word sampled from the entire vocabulary, regardless of the length and context o…