EmphTTS: an emphasis-control TTS with reinforcement learning
On the map: Deep reinforcement learning methods → RL training of language and agent models
Abstract (arXiv)
Generating controllable and human-like emphasis remains an open challenge in text-to-speech, even when explicit emphasis control signals are provided in the text input, limiting the communicative accuracy of synthetic speech in real-world applications. Reinforcement learning has recently shown promise for post-training TTS systems to align with human preference, yet existing methods have not been applied to word-level prosodic control. We present EmphTTS, a non-autoregressive TTS system that applies Group Relative Policy Optimization (GRPO) to the duration predictor with an emphasis localization reward, enabling direct optimization for word-level emphasis. Evaluations show that EmphTTS achieves the best emphasis controllability and performs the best in emphasis objective evaluation. In subjective preference tests, EmphTTS is significantly preferred over synthetic groundtruth and most baselines. Ablation studies show that GRPO improves emphasis realization beyond supervised-finetuning-based duration modeling and simple speaking-rate adjustment, while alleviating the mismatch between the independently trained duration predictor and TTS model.
Key facts. No citing papers in the map yet (data through 14 Oct 2026). Placed in RL training of language and agent models, one of 15 directions in Deep reinforcement learning methods. Builds on 28 of its 34 references that are in the map. First posted on arXiv 23 Sep 2026.
Builds on
28 of 34 references.
References · 28
- 2024DeepSeekMath: Pushing the Limits of Mathematical Reasoning in Open Language Modelscited by 9,379
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16 more
- 2023CAM++: A Fast and Efficient Network for Speaker Verification Using Context-Aware Maskingcited by 102
- 2023LibriTTS-R: A Restored Multi-Speaker Text-to-Speech Corpuscited by 101
- 2023EXPRESSO: A Benchmark and Analysis of Discrete Expressive Speech Resynthesiscited by 98
- 2021Large-scale Self-Supervised Speech Representation Learning for Automatic Speaker Verificationcited by 78
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- 2025Group Relative Policy Optimization for Text-to-Speech with Large Language Modelscited by 7
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- 2025No Verifiable Reward for Prosody: Toward Preference-Guided Prosody Learning in TTScited by 4
- 2026Knowing What to Stress: A Discourse-Conditioned Text-to-Speech Benchmarkcited by 1
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- 2024Enhancing Zero-shot Text-to-Speech Synthesis with Human Feedback
- 2025F5R-TTS: Improving Flow-Matching based Text-to-Speech with Group Relative Policy Optimization
- 2025Multi-Reward GRPO for Stable and Prosodic Single-Codebook TTS LLMs at Scale
- 2025EmoSteer-TTS: Fine-Grained and Training-Free Emotion-Controllable Text-to-Speech via Activation Steering
- 2025Explore the Reinforcement Learning for the LLM based ASR and TTS system
- 2025TTS-CtrlNet: Time varying emotion aligned text-to-speech generation with ControlNet
- 2026VoiceTTA: Enhancing Zero-Shot Text-to-Speech via Reinforcement Learning-Based Test-Time Adaptation
- 2026FlowTTS-GRPO: Online Reinforcement Learning with Multi-Objective Reward Optimization for Flow-Matching Based Text-to-Speech