Think in Sentences: Explicit Sentence Boundaries Enhance Language Model's Capabilities

arXiv cs.CL / 4/14/2026

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Key Points

  • 既存研究がダミートークン挿入に注目する一方で、自然言語が本来持つ文境界という構造を活用できていない点を問題提起しています。
  • 提案手法では、LLM入力における文境界へ区切り(delimiter)を挿入することで、ダミートークンを文脈に統合しつつ推論を「文ごと」に扱う挙動を促します。
  • 手法はin-context learningと教師あり微調整の2方式を検証し、7B〜600BのDeepseek-V3スケールで実験されています。
  • 多様なタスクで一貫した改善が見られ、特にGSM8kで最大7.7%、DROPで最大12.5%の向上が報告されています。

Abstract

Researchers have explored different ways to improve large language models (LLMs)' capabilities via dummy token insertion in contexts. However, existing works focus solely on the dummy tokens themselves, but fail to leverage the inherent sentence-level structure of natural language. This is a critical oversight, as LLMs acquire linguistic capabilities through exposure to human-generated texts, which are inherently structured at the sentence level. Motivated by this gap, we propose an approach that inserts delimiters at sentence boundaries in LLM inputs, which not only integrates dummy tokens into the context, but also facilitates LLMs with sentence-by-sentence processing behavior during reasoning. Two concrete methods: (1). In-context learning and (2). Supervised fine-tuning are experimented using 7B models to 600B Deepseek-V3. Our results demonstrate consistent improvements across various tasks, with notable gains of up to 7.7\% on GSM8k and 12.5\% on DROP. Furthermore, the fine-tuned LLMs can incorporate sentence awareness evidenced by their internal representations. Our work establishes a simple yet effective technique for enhancing LLM's capabilities, offering promising directions for cognitive-inspired LLM enhancement paradigm.