I know that according to a question asked by another user here Are the Apple text-to-speech voices copyrighted?
"No other use of the System Voices is permitted by this License, including but not limited to the use, reproduction, display, performance, recording, publishing or redistribution of any of the System Voices in a profit, non-profit, public sharing or commercial context."
But what is that License? Is it a patent or is it copyright? What kind of protection does the license include? At what point do these protections actually limit use?
I am considering Radiohead's Fitter Happier song for instance.