eSpeak NG Text-to-Speech is released under the GPL version 3 or later license (https://github.com/espeak-ng/espeak-ng/blob/master/COPYING)
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.

The eSpeak provided is about the latest available version at the time of the mod's build process
You can view (https://github.com/espeak-ng/espeak-ng) for its source code
