I'm using https://github.com/espeak-ng/espeak-ng for generating sound to be used later
For example I run this command
C:\Program Files\eSpeak NG>espeak-ng.exe -v en -w %TEMP%\test.wav speak
Am I permitted to use the wav file for commercial use? I can't work out what license the default voice is under (or to be more specific the resulting wav)