The world of Text-to-Speech (TTS) has seen remarkable progress in recent years, largely thanks to the growing number of high-quality, open-weight models. Whether you're building voice assistants, narrating articles, or developing creative voice synthesis tools, open-weight TTS models offer flexibility, transparency, and freedom from licensing constraints that proprietary APIs can’t match.
In this post, we’ll explore some of the best open-weight TTS models available in 2025, comparing their capabilities, strengths, and use cases.
🌟 1. XTTS by Coqui.ai
Model: XTTS v2
Highlights:
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Multilingual (supports over 10 languages)
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Speaker cloning with just a few seconds of audio
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Open-weight and fine-tunable
Why it's great:
XTTS combines high-quality synthesis with multilingual capabilities and zero-shot voice cloning. It’s particularly impressive in preserving speaker characteristics and intonation, making it ideal for character voices, dubbing, and narration.
Use Cases: Voice cloning, audiobooks, multilingual apps
License: Apache 2.0
🔊 2. Bark by Suno
Model: Bark (2023, still widely used in 2025)
Highlights:
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Text-to-audio (not just speech – also music and sound effects)
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Multilingual and expressive
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Emulates non-verbal sounds (e.g., laughter, sighs)
Why it's great:
Bark broke new ground by generating not only speech but also music and audio cues. Its voice quality and naturalness are strong, though it can be harder to fine-tune or control precisely.
Use Cases: Creative projects, synthetic podcasts, audio storytelling
License: MIT
🧠3. Tortoise TTS by James Betker
Model: Tortoise TTS
Highlights:
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Ultra-realistic voices with expressive delivery
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Designed for long-form content
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Good zero-shot speaker cloning
Why it's great:
Tortoise TTS excels in generating expressive, pause-filled, natural-sounding narration. It’s slower than others but great for generating believable character voices for audiobooks or long-form narration.
Use Cases: Audiobooks, character voices, immersive narration
License: Creative Commons (non-commercial)
🎙 4. OpenVoice by MyShell
Model: OpenVoice v2
Highlights:
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Real-time voice cloning with style control
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High-quality output with fast inference
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Emphasis on ease of use
Why it's great:
OpenVoice stands out for its ability to not only clone voices quickly but also let you modulate aspects like speaking style, speed, and emotional tone. This makes it ideal for applications needing personalized, expressive speech synthesis.
Use Cases: Voice chat, content creation, real-time applications
License: Apache 2.0
🔧 5. ESPnet-TTS
Model: ESPnet2-TTS (multiple variants like Tacotron2, FastSpeech2, VITS)
Highlights:
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Research-grade flexibility
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Supports multiple TTS architectures
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Strong multilingual and vocoder support
Why it's great:
If you’re looking for a modular and research-oriented TTS framework, ESPnet-TTS is one of the best. You can experiment with various encoder-decoder models and vocoders, making it ideal for academic or experimental use.
Use Cases: Research, custom TTS pipeline development
License: Apache 2.0
⚖️ Comparison Table
| Model | Speaker Cloning | Multilingual | Expressiveness | License | Best For |
|---|---|---|---|---|---|
| XTTS | ✅ Zero-shot | ✅ | ✅ | Apache 2.0 | Voice cloning, narration |
| Bark | ✅ | ✅ | ✅ (incl. SFX) | MIT | Audio stories, creative apps |
| Tortoise | ✅ | 🚫 (mostly English) | ✅✅✅ | CC-NC | Audiobooks, storytelling |
| OpenVoice | ✅ Fast | ✅ | ✅ | Apache 2.0 | Real-time apps, content creation |
| ESPnet-TTS | ❌ (limited) | ✅ | Depends on model | Apache 2.0 | Research, flexible pipelines |
🧩 Final Thoughts
Open-weight TTS models are rapidly closing the gap with proprietary offerings from companies like ElevenLabs and Google. The best model for you will depend on your specific goals—whether you prioritize naturalness, speed, multilingual capabilities, or flexibility.
If you’re just getting started, XTTS or OpenVoice are great general-purpose choices. For expressive long-form generation, Tortoise TTS still shines. And if you’re an audio creative or researcher, Bark and ESPnet offer unique capabilities worth exploring.
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