What makes it llm generated to me is that somehow it is hard to read.

What I mean is that each sentence looks well made and from a highly skilled writer. But reading a few parameters I'm lost quite fast. Like if there was no coherence or progression. Just some ideas sometimes even repeated in random order even if in the end there is point/explanation to be made.

Like when Claude or another llm drops you a 5 pages block of text or MD spec that is totally unreadable even if it is supposed to make sense.

I think that it is unusual for human generated speech because usually if you have good with words and to do great sentences, you will also to do it in logical and coherent way at the multiple paragraphs level too. Or at the opposite, if you don't know how to redact proper paragraphs, you will. It not be able to do great sentences anyway.