Don't check "support Firefox for Android" when submitting your add-on if you never test it. This add-on doesn't work on it.

Doesnt have tts voice select. kinda useless

A proposta é boa, mas o recurso "Auto detects language" não funciona bem.

This isnt working on linux :/ it not give any errors, the play button show up and all but no sound.

you need to be able to control the speed of the speech. as well as a choice of different voices.
generally ok but i find it hard to keep up with such a fast speed.
which defeats the purpose!

Никакой АПИ не читает по-русски.

It works which is more than I can say for a lot of add-ons but that voice is terrible. I can hardly understand it. It's like they dug up the old Dr. Sbaitso voice and sped it up. With that old of a voice generator it would at least be helpful if there were options to control its tone, pitch, and speed to fit the user and make it more understandable.
As it currently stands it's fairly unusable.
I applaud the effort, but unless you can get a voice made this century I can't see myself using it.
(I understand licensing may be an issue; can't say that I know how availability of different voices works for these types of projects.)