Wow is that completely underwhelming the text to speech support of Firefox (Linux), tried it for the first time with your “read aloud” button. I can’t even understand it, it is that bad. I’m sure I heard better text to speech software 20 years ago. What is going on here?
Edit: on ungoogled chromium the button doesn’t even work :-P
That’s probably espeak on Linux and it sounds horrible indeed. On my Android phone or on Windows, it sounds much much better.
Have you ever tried the speak feature in Firefox reader mode on Linux? Same problem there.