The perfect add-ons to use Edge voices for Firefox. Do note though that for different languages, you need to enter the name in "Or enter custom voice:".
For example, I want Japanese female voice, I enter "ja-JP-NanamiNeural"

The best TTS extension ever. Edge TTS does not work on Linux, so this is the only way I can have it, and actually is much better than the native Edge browser TTS in PC and Android alike.

This work as intended! Really helped me now i can use edge natural voices such as pt-BR-ThalitaNeural and read news way better ty kind dev!

This extension does not work fo me because thera are on
ly english speaking voices.

Des voix d'une grande qualité.
Un module parfait pour une utilisation basique.
Merci.
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A l'attention des utilisateurs qui se plaignent de ne trouver que des voix anglaises.
Pour changer de voix ou de langues, il suffit de cliquer sur tts.travisvn.com. Une nouvelle fenêtre s'ouvre. Cherchez et choisissez la voix qui vous convient. Cliquez dessus et elle est copiée automatiquement dans le presse-papier. Revenez à la première fenêtre, un simple clic droit (Coller) dans "Custom voice name" résout votre problème.

doesn't work on reddit.com

This works very well, although there are some areas for improvement:

+ Its parser reads all the text of site elements. This means that texts like "Login, Navigation" are also read.

+ It might be better to use just-in-time requests rather than generating all possible site text before sending requests, which would force the user to wait a while before listening to the site.