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eSpeak NG: Speech Synthesizer
eSpeak NG is a compact open source software speech synthesizer for English and other languages, for Linux and Windows.
eSpeak NG uses a "formant synthesis" method. This allows many languages to be provided in a small size. The speech is clear, and can be used at high speeds, but is not as natural or smooth as larger synthesizers which are based on human speech recordings.
eSpeak NG is available as:
- A command line program (Linux and Windows) to speak text from a file or from stdin.
- A shared library version for use by other programs. (On Windows this is a DLL).
- A SAPI5 version for Windows, so it can be used with screen-readers and other programs that support the Windows SAPI5 interface.
- eSpeak NG has been ported to other platforms, including Solaris and Mac OSX.
Features
- Includes different Voices, whose characteristics can be altered.
- Can produce speech output as a WAV file.
- SSML (Speech Synthesis Markup Language) is supported (not complete), and also HTML.
- Compact size. The program and its data, including many languages, totals about 1.4 Mbytes.
- Can be used as a front-end to MBROLA diphone voices. eSpeak NG converts text to phonemes with pitch and length information.
- Can translate text into phoneme codes, so it could be adapted as a front end for another speech synthesis engine.
- Potential for other languages. Several are included in varying stages of progress. Help from native speakers for these or other languages is welcome.
- Written in C.
The eSpeak speech synthesizer supports over 70 languages, however in many cases these are initial drafts and need more work to improve them. Assistance from native speakers is welcome for these, or other new languages. Please contact me if you want to help.
History
The program was originally known as speak and originally written for Acorn/RISC_OS computers starting in 1995 by Jonathan Duddington. This was enhanced and re-written in 2007 as eSpeak, including a relaxation of the original memory and processing power constraints, and with support for additional languages.
In 2010, Reece H. Dunn started maintaining a version of eSpeak on GitHub that was designed to make it easier to build eSpeak on POSIX systems, porting the build system to autotools in 2012. In late 2015, this project was officially forked to a new eSpeak NG project. The new eSpeak NG project is a significant departure from the eSpeak project, with the intention of cleaning up the existing codebase, adding new features and adding and improving to the supported languages.