Here is a short little video I made about the Librera/Ivona Text to speech functionality in practice, so you can gage whats involved, to get it started once you've set it up (Librera usually defaults right into the last read book, this time it didn't, probably exited once before.):
https://streamable.com/64m7i
Audio on the video is only set to half in the player, so pull it up, you need it.

(Audio levels and my smartphone I tells ya..

)
Just as a memento of what is possible - that especially amazon isnt tapping in yet (because they own the company that created those voices...

).
Pairing the likebook to a bluetooth speaker is pretty easy as well, and yes, it does remember its last paired device.