Jun 29, 2010
Dec 12, 2018
Reece H. Dunn (rhdunn)
Menny Even Danan (menny)
Reece H. Dunn (rhdunn)
Show all (33)33
Source code

Show card

The espeak-ng sources contain the code for the Android™ port of the application. This is published as the eSpeak for Android program on the Google Play store. It is based on the eyes-free port of eSpeak to the Android platform. This code was originally maintained in a separate branch when the repository tracked eSpeak releases.


In order to build the Android APK file, you need:

  1. the Android SDK with API 21 support;
  2. the Android NDK;
  3. Gradle 2.1 or later.

In order to use Android Studio, you will also need:

  1. Android Studio.

Building with Gradle

  1. Set the location of the Android SDK:

    $ export ANDROID_HOME=<path-to-the-android-sdk>
  2. Build the project:

    $ ./
    $ ./configure --with-gradle=<path-to-gradle>
    $ make apk-release

This will create an android/build/outputs/apk/espeak-release-unsigned.apk file.

Signing the APK

In order to install the built APK you need to self-sign the package. You can do this by:

  1. Creating a certificate, if you do not already have one:

    $ keytool -genkey -keystore [YOUR_CERTIFICATE] -alias [ALIAS]
  2. Sign the package using your certificate:

     $ jarsigner -sigalg MD5withRSA -digestalg SHA1 \
       -keystore [YOUR_CERTIFICATE] \
       android/build/outputs/apk/espeak-release-unsigned.apk [ALIAS]
  3. Align the apk using the zipalign tool.

     $ zipalign 4 android/build/outputs/apk/espeak-release-unsigned.apk \


Now, you can install the APK using the adb tool:

$ adb install -r android/build/outputs/apk/espeak-release-signed.apk

After running, eSpeakActivity will extract the file into its own data directory to set up the available voices.

To enable eSpeak, you need to:

  1. go into the Android Text-to-Speech settings UI;
  2. enable eSpeak TTS in the Engines section;
  3. select eSpeak TTS as the default engine;
  4. use the Listen to an example option to check if everything is working.


The documentation for eSpeak NG provides:

  1. a user guide;
  2. a guide for language and voice authors; and
  3. details for developers.

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 Compatibility

The espeak-ng binaries use the same command-line options as espeak, with several additions to provide new functionality from espeak-ng such as specifying the output audio device name to use. The build creates symlinks of espeak to espeak-ng, and speak to speak-ng.

The espeak speak_lib.h include file is located in espeak-ng/speak_lib.h with an optional symlink in espeak/speak_lib.h. This file contains the espeak 1.48.15 API, with a change to the ESPEAK_API macro to fix building on Windows and some minor changes to the documentation comments. This C API is API and ABI compatible with espeak.

The espeak-data data has been moved to espeak-ng-data to avoid conflicts with espeak. There have been various changes to the voice, dictionary and phoneme files that make them incompatible with espeak.

The espeak-ng project does not include the espeakedit program. It has moved the logic to build the dictionary, phoneme and intonation binary files into the file that is accessible from the espeak-ng command line and C API.

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.


Test latest development version at eSpeakNG online.

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

Look at and subscribe to eSpeakNG mailing list to view and discuss other related topics.

License Information

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

The ieee80.c implementation is taken directly from ToFromIEEE.c.txt which has been made available for use in Open Source applications per the license statement on The only modifications made to the code is to comment out the TEST_FP define to make it useable in the eSpeak NG library, and to fix compiler warnings.

The getopt.c compatibility implementation for getopt support on Windows is taken from the NetBSD getopt_long implementation, which is licensed under a 2-clause BSD license.

Android is a trademark of Google Inc.