It doesn’t sound like real actual people talking because it’s not real actual people talking.

Try something for me. Type a sentence, any sentence, on your phone. Then mash the middle suggested next word button about fifty times.

Congratulations, you’re an AI! Well, that’s a very simplified version of what generative AI does, it takes your text and then predicts the likely “next” text again and again until it either runs out of room or predicts “text ends here”. Yes there’s some preamble, and it’s not using the same dictionary, and it’s not predicting word-by-word but token-by-token, and there’s some randomness thrown in for spite, but that’s about the size of it.