Pied

Pied is an open source tool for managing text-to-speech voices under Linux. It integrates advanced neural speech synthesis models with the speech-dispatcher system, allowing existing Linux software (such as screen readers, browsers and ebook readers) to take advantage of natural sounding voices.

It's written using Dart and Flutter, and packaged both as a Flatpak and a Snap, and is available via the Snap Store.

Further information can be found on the Pied website: https://pied.mikeasoft.com

The full source code is available on GitHub: https://github.com/Elleo/pied