Greasy Fork is available in English.
Reads aloud most sentences in Duo's challenges.
Little script to provide listening function to all the words and phrases in Duolingos lessons.
Still in beta, but usable. Some challenges might not work or not as expected.
Hear every phrase you want and only listen to one single voice instead a whole bunch of cartoon characters.
You can configure it, what to speak and what not.
If you're missing your learning language you have the option to install it to Windows 10:
https://support.microsoft.com/en-us/topic/how-to-download-text-to-speech-languages-for-windows-10-d5a6b612-b3ae-423f-afa5-4f6caf1ec5d3