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eSpeak NG Text-to-Speech

The eSpeak NG (Next Generation) Text-to-Speech program is an open source speech synthesizer that supports over 70 languages. It is based on the eSpeak engine created by Jonathan Duddington. It uses spectral formant synthesis by default which sounds robotic, but can be configured to use Klatt formant synthesis or MBROLA to give it a more natural sound.

See the CHANGELOG for a description of the changes in the various releases and with the eSpeak project.

Build Dependencies

In order to build eSpeak NG, you need:

  1. a functional autotools system (make, autoconf, automake, libtool and pkg-config);
  2. a functional c compiler that supports C99 (e.g. gcc or clang).

Optionally, you need:

  1. the pcaudiolib development library to enable audio output;
  2. the sonic development library to enable sonic audio speed up support;
  3. the ronn man-page markdown processor to build the man pages.

To build the documentation, you need:

  1. the kramdown markdown processor.


Core dependencies:

Dependency Install
autotools sudo apt-get install make autoconf automake libtool pkg-config
c99 compiler sudo apt-get install gcc

Optional dependencies:

Dependency Install
sonic sudo apt-get install libsonic-dev
ronn sudo apt-get install ruby-ronn

Documentation dependencies:

Dependency Install
kramdown sudo apt-get install ruby-kramdown


The first time you build eSpeak NG, or when you want to change how to build eSpeak NG, you need to run the following standard autotools commands:

./configure --prefix=/usr

NOTE: The --prefix option above will install the files to the /usr directory, instead of the default /usr/local location. You can use other standard configure options to control the output. For more information, you can run:

./configure --help

To use a different compiler, or compiler flags, you can specify these before the configure command. For example:

CC=clang-3.5 CFLAGS=-Wextra ./configure --prefix=/usr

The espeak-ng and speak-ng programs, along with the espeak-ng voices, can then be built with:


NOTE: Building the voice data does not work when using the -jN option. If you want to use that option, you can run:

make -j8 src/espeak-ng src/speak-ng

The documentation can be built by running:

make docs

Specific languages can be compiled by running:

make LANG

where LANG is the language code of the given language. More information can be found in the Adding or Improving a Language documentation.

Audio Output Configuration

The following configure options control which audio interfaces to use:

Option Audio Interfaces Default
--with-pulseaudio PulseAudio yes
--with-portaudio PortAudio yes
--with-sada SADA (Solaris) no

If pulseaudio and portaudio are both enabled and available, eSpeak NG will choose which one to use at runtime, trying pulseaudio first before falling back to portaudio.

eSpeak NG Feature Configuration

The following configure options control which eSpeak NG features are enabled:

Option Description Default
--with-klatt Enable Klatt formant synthesis. yes
--with-mbrola Enable MBROLA voice support. yes
--with-sonic Use the sonic library to support higher WPM. yes
--with-async Enable asynchronous commands. yes

NOTE: The --with-sonic option requires that the sonic library and header is accessible on the system.

Extended Dictionary Configuration

The following configure options control which of the extended dictionary files to build:

Option Extended Dictionary Default
--with-extdict-ru Russian no
--with-extdict-zh Mandarin Chinese no
--with-extdict-zhy Cantonese no

The extended dictionaries are taken from and provide better coverage for those languages, while increasing the resulting dictionary size.

Compiling on Windows

NOTE: This is currently experimental. It does not build the voice data, and may contain runtime errors and missing functionality.

To build eSpeak NG on Windows, you will need:

  1. a copy of Visual Studio 2015, such as the Community Edition;
  2. the Windows 8.1 SDK;
  3. the WiX installer plugin;
  4. the pcaudiolib project checked out to src (as src/pcaudiolib).

You can then open and build the src/windows/espeak-ng.sln solution in Visual Studio.


Before installing, you can test the built espeak-ng using the following command from the top-level directory of this project:


The ESPEAK_DATA_PATH variable needs to be set to use the espeak-ng data from the source tree. Otherwise, espeak-ng will look in $(HOME) or /usr/share/espeak-data.

The LD_LIBRARY_PATH is set as espeak uses the shared library. This ensures that espeak uses the built shared library in the src directory and not the one on the system (which could be an older version).


You can install eSpeak NG by running the following command:

sudo make LIBDIR=/usr/lib/x86_64-linux-gnu install

NOTE: The LIBDIR path may be different to the one on your system (the above is for 64-bit Debian/Ubuntu releases that use the multi-arch package structure -- that is, Debian Wheezy or later).

You can find out where espeak-ng is installed to on your system if you already have an espeak-ng install by running:

find /usr/lib | grep libespeak-ng


The main documentation for eSpeak NG provides more information on using and creating voices/languages for for eSpeak NG.

The espeak-ng and speak-ng command-line documentation provide a reference of the different command-line options available to these commands with example usage.

eSpeak for Android

The android branch contains the sources for the eSpeak for Android program, based on the eyes-free port of eSpeak to Android.

Historical Versions

The historical branch contains the available older releases of the original eSpeak that are not contained in the subversion repository.

1.24.02 is the first version of eSpeak to appear in the subversion repository, but releases from 1.05 to 1.24 are available at

These early releases have been checked into the historical branch, with the 1.24.02 release as the last entry. This makes it possible to use the replace functionality of git to see the earlier history:

git replace 8d59235f 63c1c019

NOTE: The source releases contain the big_endian, espeak-edit, praat-mod, riskos, windows_dll and windows_sapi folders. These do not appear in the source repository until later releases, so have been excluded from the historical commits to align them better with the 1.24.02 source commit.


Report bugs to the espeak-ng issues page on GitHub.

License Information

eSpeak NG Text-to-Speech is released under the GPL version 3 or later license.