6 Best Open Source TTS Models in 2025

The demand for open source text to speech technology has grown rapidly in recent years due to its capability of analyzing text and producing lifelike, expressive voices without expensive licensing fees. Unlike commercial tools, the open source voice synthesizer provides greater control to customize voices, improve models, and adapt them for diverse use cases, from accessibility tools and educational platforms to virtual assistants and creative media. In this article, you’ll explore the best open source TTS models and discuss how to make the right choice for your project.

Part 1: Top 6 Open Source AI Text to Speech Generators

Here are the six best TTS models that combine advanced AI voice synthesis, natural speech quality, and flexible integration for developers. Let’s dive into their details:

1. eSpeak

eSpeak is a lightweight and easy-to-use text to speech open source JS model that helps generate clear and smart speech at a fast speed. It supports over 40 languages and works on Windows, macOS, Linux, and Android. Though the voice output sounds robotic, it’s used for accessibility and assistive tools, where resources are limited.

Best for: Screen readers, robotics, and embedded systems

2. Fish Speech

Fish Speech is a leading open source AI text to speech model with an innovative DualAR architecture. Developed for research and production, it delivers very precise voice quality and customizable speech. It supports text input in multiple languages with hours of training data for English, Chinese, and Japanese. You can also clone voices with 10-30 second samples.

Best for: Developers seeking neural TTS for superior quality

3. Mozilla TTS

Mozilla TTS is a popular open source TTS engine that incorporates advanced neural network architectures, especially sequence-to-sequence models to generate natural speech. Built using deep learning, it allows fine-tuning for custom voice creation and supports multiple backends like Tacotron 2, Glow-TTS, and HiFi-GAN. It even allows training your voice models using your own dataset.

Best for: Accessibility, research, and custom voice projects

4. MaryTTS

Developed in Java, MaryTTS is a versatile open source voice synthesizer with a modular design. It not only helps build custom text to speech systems but also supports creating new voices from audio recordings. What makes this open TTS model stand out is the natural sounding speech, flexible input format, multilingual support, and high customization capabilities.

Best for: Education, language learning, and research

5. Kokoro

Kokoro is a modern yet lightweight open source text to voice model known for clear, expressive voice output and a fast speed. Built with advanced neural network architectures, it delivers smooth, natural intonation and supports multiple languages. It’s designed for both researchers and developers who want professional-grade voice synthesis without depending on commercial APIs.

Best for: Content creators, educators, and app developers

6. ChatTTS

ChatTTS by OpenAI is an innovative open source AI voice generator optimized for conversational applications. It excels at producing natural, context-aware speech in English and Chinese. You can also control elements like pauses and laughter for flexibile dialogue delivery. Its other features include multi-speaker synthesis, voice conditioning, and support for audio generation using Python scripts.

Best for: AI chatbots, virtual assistants, and real-time agents

Part 2: What to Consider when Choosing Opensource TTS Models

Selecting the best open source text to speech tool depends on your project’s requirements. However, here are a few key factors to consider:

1. Speech Quality: The quality of the synthesized speech is important. Look for an open TTS model that can produce smooth, expressive, and natural-sounding speech.

2. Language Support: Some models specialize in English, while others support various languages and accents. Always ensure the chosen model supports the language you need.

3. Customization Features: To enhance user experience, choose an opensource text to speech tool that allows you to fine-tune voice pitch, speed, and emotional tone.

4. Resource Requirements: TTS models may need GPUs and significant processing power to train or run efficiently. Find a lightweight option for low-resource environments.

5. Latency: Fin low latency model for fast text to voice conversion, especially for real-time interactions like chatbots or voice assistants.

6. Usage Rights: Open source licenses vary. Some permit commercial use, while others have restrictions. Always review the license to ensure compliance with your requirements.

Part 3: Best Free Text to Speech Generator Online

While text to speech open source systems are great for developers, non-technical users often prefer online tools. In this regard, BlipCut AI Voiceover should be the way to go.

This remarkable browser-based TTS tool helps generate high-quality commercially usable voices for professional content like ads or marketing videos. You can also access its library of over 1300 realistic voices in a variety of languages. In addition, it uses cutting-edge technology to instantly transform written words into lifelike speech with high precision.

Steps to Use Text to Speech Generator Online:

• Step 1. Access the TTS Tool

  The first step is to open the official BlipCut website and click “More Tools” to select the “Text to Speech” tool. Now, tap the “Create Voiceover” tab to proceed.

  

• Step 2. Input Text and Select Voice

  It’s time to type the script and choose the desired voice and the language. You can also add pauses or blocks if needed. Then, press “Voiceover” at the bottom.

  

• Step 3. Download Audio

  Once the voiceover is generated, listen to it. If it’s okay, hit the “Download” tab and pick the “Audio” or “Script” option. That’s all!

  

Conclusion

Today, text to speech technology is more powerful and accessible than ever. Whether you want to create a custom voice assistant, localize content, or experiment with voice synthesis, this post has provided open source AI text to speech options for developers and creators alike. You can choose the one that suits your needs. However, if you need a free text to speech generator online, try BlipCut Voiceover for its user-friendly interface and high-quality output.