Top Eight Open Source Text to Speech Software of 2024

Text to speech technology has revolutionized the way users interact with digital content. Initially, the landscape was dominated by proprietary systems. However, factors such as high costs, restrictive licensing, and a lack of customization options posed a significant barrier to individuals looking to utilize TTS technology for enhanced accessibility. The need for open source text to speech engines originated to tackle all challenges of proprietary systems.

What is Open Source Text to Speech? 

Open source text to speech converts written text into spoken words using synthetic voices, and unlike proprietary TTS solutions, provides businesses with the freedom to modify, enhance, and redistribute the software’s source code. This flexibility empowers organizations to tailor the TTS technology to their specific needs while fostering innovation and adaptability.

The availability of countless open-source TTS engines makes it difficult for individuals to choose one that suits their budget and business needs. This blog lists the top eight open source text to speech engines available. But, before moving any further, let’s understand some advantages of utilizing open-source TTS engines.

Benefits of Open Source Text to Speech  

An open-source TTS engine provides users with a myriad of benefits:

Cost-Effectiveness

An open-source software eliminates the need for expensive licensing fees associated with proprietary solutions. Businesses can access and modify the source code without the burden of additional costs.

Customization and Flexibility

Developers can tailor the TTS technology to meet their unique requirements. This flexibility is crucial for industries with specific jargon, terminology, or language nuances. The ability to modify the source code empowers developers to integrate TTS seamlessly into existing systems.

Community-Driven Development

Businesses leveraging a TTS open-source engine benefit from regular updates, improvements, and new features driven by a collaborative network of developers. Community support also provides a wealth of knowledge and facilitates quicker issue resolution, ensuring the technology stays at the forefront of industry standards.

Scalability

Open-source TTS solutions are designed to scale effortlessly while accommodating growing business needs without compromising performance. This scalability is advantageous for enterprises with fluctuating workloads and ensures that TTS capabilities remain robust during peak usage.

Eight Best Open Source Text to Speech Engines

Here are the best open-source speech synthesis engines available in the digital space:

Coqui AI

Coqui is an entirely free text to speech library that offers vocoder and per-trained TTS models as part of its package. While the foundation model XTTS developed by Coqui’s team generates voices in 13 different languages, XTTSv2 comes with 16 languages and enhanced performance.

The platform excels in fast and efficient model training backed by detailed training logs, support for multi-speaker TTS, and a feature-complete Trainer API. Coqui has emerged as a solution for businesses seeking natural-sounding human speech for diverse applications like voice assistants, automated customer service, and speech-enabled devices.

Mozilla TTS

Mozilla TTS is an open-source text to speech synthesis system developed by the Mozilla Foundation. It aims to support numerous languages to cater to the diverse linguistic needs of users and developers worldwide. The system is built on deep learning techniques, leveraging neural network models to generate natural-sounding speech.

It allows users to train and fine-tune their models based on specific datasets and requirements. Mozilla TTS benefits from contributions and feedback from a community of developers and researchers. The speech recognition solution represents Mozilla’s commitment to promoting open-source, privacy-aware technologies in the realm of speech synthesis. 

MaryTTS

MaryTTS stands out as an open-source, multilingual speech synthesis system developed in Java. It allows users to access, modify, and distribute the source code under the LGPLv3 license. MaryTTS supports many languages and dialects while offering customizable voices and pronunciation rules. Due to its Java-based design, MaryTTS can operate on various platforms like Windows, Linux, and macOS.

It is extensible, as users can incorporate new voices, languages, and functionalities through plugins and modules. MaryTTS attracts developers seeking customization, researchers exploring text to speech algorithms, and individuals in search of a free, open-source speech recognition solution for non-commercial purposes.  

eSpeak

eSpeak is a free, compact, open-source speech synthesis platform that converts text into voice files using a formant synthesis method. It supports over 100 languages and accents through optional data packs. The platform offers multiple voices while allowing alterations within defined limits.

It produces voice output in the form of WAV files and is partially compatible with HTML and SSML. eSpeak can translate text into phoneme codes, making it adaptable to other speech synthesis engines. Written in C, it provides development tools for creating and refining phoneme data.

Due to its compact size and multilingual support, eSpeak has been incorporated into the NVDA open-source screen reader, which is available on Windows, Android, Ubuntu, and other Linux distributions.

YakiToMe

YakiToMe is a web-based speech recognition engine designed to convert text into audio files for various purposes, such as creating podcasts, listening to ebooks, or learning a new language.

The platform offers several notable features, including the selection of voices in multiple languages, including English, Spanish, French, and German.

Users can convert text into different file formats, such as MP3, WAV, or OGG. YakiToMe offers a free plan with limited features and paid plans with more features and higher usage limits.

Mimic

Mimic, developed by Mycroft AI, encompasses two distinct text to speech engines: Mimic 1 and Mimic 3, each tailored to specific needs.

Released in 2017, Mimic 1 is ideal for basic applications prioritizing lightweight and fast performance and where voice quality is not a primary concern. It offers multiple voices with different styles based on speech modeling techniques. While open-source for non-commercial use, it has limitations such as simpler voice quality and fewer customization options.

Launched in 2020, Mimic 3 employs neural networks for more natural-sounding and nuanced speech. It is ideal for users valuing natural-sounding voices, offline operation, and privacy but requires more technical expertise. However, it is still under active development, with fewer available voices and features.

MBROLA

MBROLA is a text to speech synthesis software developed by the TCTS Lab of the Faculté Polytechnique de Mons in Belgium. MBROLA works on a phoneme-based synthesis approach, generating speech by combining and modifying pre-recorded phonemes.

MBROLA provides different voices with variations in pitch, speed, and other parameters, allowing for some customization. Its extensive language support and ease of integration make it a valuable speech synthesis tool, especially when a specific language or accent is a priority.

ESPnet-TTS

ESPnet-TTS is an open-source end-to-end speech processing toolkit developed by the Center for Language and Speech Processing at Johns Hopkins University.

It is designed for various speech-related tasks, such as speech translation, recognition, enhancement, and more. ESPnet utilizes PyTorch as its deep learning engine to convert text directly into voice files.

The platform’s multilingual support makes it the first choice for researchers and developers working on speech-processing tasks in various linguistic contexts. It is particularly recognized for its modular architecture and comprehensive functionality in automatic speech recognition and text to speech.

Cons of Open Source TTS Engines

While open source text to speech engines offer several advantages, including cost-effectiveness, customization, and community-driven development, there are also potential downsides to consider.

Reliability and Security Concerns

Open-source projects typically rely on community support, which can be inconsistent. Access to timely, professional support may be limited, particularly for less popular or newer projects.

Voice Quality Variability

The quality of synthesized speech in open-source TTS engines can vary. While some engines provide high-quality, natural-sounding voices, others may lag behind proprietary engines in terms of clarity and expressiveness.

Limited Language Support

Open-source TTS engines might offer limited support for languages and dialects compared to some proprietary solutions that have invested heavily in expanding their language portfolios.

Security Risks

Open-source projects might not undergo the same level of security scrutiny or regular security updates as proprietary software, potentially exposing users to vulnerabilities.

Incomplete Documentation

Documentation for open source projects can sometimes be lacking or outdated, which makes it challenging for new users to implement or customize the TTS engine effectively.

Murf: An Ultimate Solution to Every Open-Source TTS Engine Constraint

Murf is an advanced text to speech generator that offers an easy-to-use interface with diverse language support, customization options, and API capabilities. It caters to the needs of creators, businesses, and developers seeking efficient, cost-effective, and high-quality audio file creation services. It is designed to address various constraints faced by open source text to speech systems. Here’s a detailed breakdown of Murf’s API features and how they serve as a solution to common challenges in the realm of TTS.

Scalability

Unlike many open-source solutions that might struggle with heavy load or lack efficient support for large-scale deployment, Murf’s API integrates into diverse systems, including IVR and conversational AI. It is engineered to support extensive operations across multiple sectors, such as call centers, virtual reality, and more.

Ease of Integration

Open-source TTS tools can be complex to integrate and may not always follow stringent security protocols. Murf, on the other hand, is built for straightforward integration that requires minimal coding effort, making it accessible even to those with limited technical expertise.

Enhanced Accessibility

Open-source TTS technologies often require additional customization to meet the needs of individuals with visual impairments or learning disabilities. Murf’s API simplifies this by providing easy access to high-quality spoken content while facilitating equal participation in the digital content landscape.

Consistency in Brand Voice

Establishing a consistent brand voice using open-source TTS can be challenging due to variability in voice quality and limited customization options. Murf offers advanced voice cloning technology that allows businesses to maintain a consistent and unique brand voice across all communications.

Conclusion

Open-source TTS engines are attractive options for businesses due to their flexibility and cost savings. However, businesses and developers should weigh their advantages against potential downsides, such as support limitations, varying quality levels, and the need for technical proficiency. By carefully evaluating their specific needs and resources, companies can make an informed decision that leverages the strengths of open-source TTS while mitigating its challenges. In doing so, they can harness the power of customizable and cost-effective solutions to enhance their applications and services.

FAQs

How does open-source TTS benefit developers?

Open-source TTS benefits developers by offering flexibility, customizability, and cost-effectiveness. Developers can modify the source code to fit their specific requirements, contribute to the community, and integrate TTS capabilities into their applications without the constraints of licensing fees.

Is open-source TTS compatible with various platforms?

Yes, many open-source TTS solutions are designed to be integrated across various operating systems and devices. This flexibility ensures developers can deploy applications with TTS capabilities on desktop, web, and mobile platforms.

Are there limitations on the languages supported by open-source text to speech?

While open-source TTS projects offer support for multiple languages, the quality and extent of support can vary significantly between languages. Popular languages like English, Spanish, and Mandarin often have better support and higher-quality voices, while less commonly spoken languages might have limited or lower-quality options.

Can open-source TTS be integrated into mobile apps?

Yes, open-source TTS can be integrated into mobile apps. Many open-source projects provide APIs or SDKs that facilitate the incorporation of TTS functionality into Android and iOS applications.

What are the advantages of using open-source text to speech?

The advantages of using open source TTS engines include cost-effectiveness, customization options, community support, transparency, and many more.