The Rise of Verbal Reinforcement Learning

arXiv:2609.01597 · cs.CL, cs.AI · Submitted 2026-09-01 · Read on arXiv

cs.CL, cs.AI

Submitted: 2026-09-01

Updated: 2026-09-01

License: http://creativecommons.org/licenses/by/4.0/

The gist: Natural language is emerging as a primary feedback channel for improving language agents, capable of conveying intent, preferences, and causal structure in forms interpretable by both humans and

Terminology

Abstract

Natural language is emerging as a primary feedback channel for improving language agents, capable of conveying intent, preferences, and causal structure in forms interpretable by both humans and modern language models. We call this paradigm Verbal Reinforcement Learning (VRL) and offer the first unified account of it. We organize the field around a single axis, when verbal feedback takes effect in an agent's lifecycle and what it modifies, yielding three pillars: (1) Language as Grounding Signal, where language defines the task itself by specifying goals, states, and reward structures; (2) Language as Deliberative Feedback, where natural language guides reasoning at test time without the need to update model parameters; (3) Language as Learning Signal, where language-based feedback shapes model parameters through training. Within each pillar, we synthesize representative work, distinguish key subcategories of approaches, and outline the distinct role language plays in shaping agent behavior. Together, this taxonomy shows how verbal reinforcement is reshaping agent development, while also defining the challenges and opportunities for building more capable and aligned agents.

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