Ideas/works/etc literally live rent-free in your head. That doesn't mean they should live rent-free in an AI's neural network.
Changing that should involve actually reducing or eliminating copyright, for everyone, not giving a special pass to AI.
Human brain most definitely is not exempt. If you read Lord of the Rings and then write down a new book, with the same characters and same story line - that's plain copying(lookup the etymology of the verb to copy). If you look at a painting and paint a very similar painting - that's still copying.
Human brains are the reason we have copyright. Your recital of passages from any copyrighted book would violate the copyright, if not for fair use doctrine. And it has nothing to do with whether you do it yourself, or have a TTS engine produce the sound.
I'm saying that AI does not and should not automatically get the exception that a human brain does.
That depends on the interpretation of "use", and it would be interesting to read what lawyers think. You learned the language largely from speech and copyrighted works. (All the stories, books, movies, etc. you ever read/heard) When you wrote this comment did you use all of them for that purpose? Is the case of AI different?
To be clear that's a rhetorical question - I don't expect anyone here to actually have a convincing enough argument either way.