ChatTTS — Expressive Text-to-Speech for Dialogue

ChatTTS Features

Natural Dialogue Speech

ChatTTS excels at conversational scenarios:

Prosody Control

# Control speaking style with parameters
params_infer = ChatTTS.Chat.InferCodeParams(
    spk_emb=None,       # Speaker embedding (None = random)
    temperature=0.3,     # Lower = more stable, higher = more expressive
    top_P=0.7,
    top_K=20,
)

# Refine prosody
params_refine = ChatTTS.Chat.RefineTextParams(
    prompt='[oral_2][laugh_0][break_6]',  # oral filler + no laugh + long breaks
)

wavs = chat.infer(
    texts,
    params_infer_code=params_infer,
    params_refine_text=params_refine,
)

Speaker Consistency

# Generate a random speaker
rand_spk = chat.sample_random_speaker()

# Use the same speaker for multiple utterances
params = ChatTTS.Chat.InferCodeParams(spk_emb=rand_spk)

wavs = chat.infer(
    ["First sentence.", "Second sentence.", "Third sentence."],
    params_infer_code=params,
)
# All 3 outputs sound like the same person

Performance

• Speed: ~5x real-time on GPU (generates 5 seconds of audio per second)
• Quality: 24kHz, natural prosody, MOS score competitive with commercial TTS
• Languages: English and Chinese
• Model size: ~800MB

Special Tokens

[laugh]     - Insert laughter
[uv_break]  - Insert a pause
[oral_0-9]  - Filler word frequency (0=none, 9=very frequent)
[laugh_0-9] - Laughter frequency
[break_0-9] - Pause frequency and duration

FAQ

Q: What is ChatTTS? A: ChatTTS is an open-source TTS model with 39,000+ GitHub stars, optimized for natural conversational speech with laughter, pauses, and emotion. Trained on 100K+ hours of dialogue data.

Q: How is ChatTTS different from Coqui TTS or Bark? A: ChatTTS is specifically optimized for dialogue — it excels at conversational prosody, laughter, and natural filler words. Coqui TTS is a general-purpose TTS toolkit. Bark generates creative audio but is slower. ChatTTS is the best choice for chatbot and assistant speech.

Q: Is ChatTTS free? A: Open-source under AGPL-3.0. Free for non-commercial use. Commercial use requires compliance with AGPL or a commercial license.