Tortoise TTS TTS
A quality-first autoregressive model — slow, but among the most realistic open-source speech available.
Wrap your text in SSML tags for precise control:
<speak><prosody rate="slow">Slow speech</prosody></speak>
Tags the selected model understands — click to drop one into your text where it happens:
This model reads plain text, so inline tags are ignored. For tag-based emotion, switch to an expressive model like Orpheus or Bark.
Define custom pronunciations (word = pronunciation):
About Tortoise TTS
Tortoise TTS, created by James Betker, deliberately trades speed for quality. It is an autoregressive multi-voice system using a DALL-E-inspired architecture, and it produces some of the most realistic synthetic speech in the open-source ecosystem, with excellent prosody and speaker similarity. The name is a nod to its pace: it is noticeably slower than most alternatives, but the payoff is studio-grade output. It supports multiple voices and voice cloning (which benefits from a longer reference, around fifteen seconds), making it a long-standing favorite for audiobooks and premium narration where wait time is acceptable. Tortoise is English-focused and released under the permissive Apache 2.0 license.
Best for: Audiobooks, premium content, quality-first applications
Browse all Tortoise TTS voicesAt a glance
- Developer
- James Betker
- License
- Apache 2.0
- Tier
- premium
- Speed
- slow
- Voice cloning
- Yes
- Languages
- English
- Max characters
- 2000