They don’t understand what they are “saying” as they generate text. LLMs can, as a result of how they are built, simply generate text that doesn’t correspond to something that is real. Generative AI, and AI more generally, is having a profound impact on the world. AI systems do make mistakes and these can be caught and corrected by a human, but it is not the same as the human making the mistake. Correcting the mistakes made by AI systems is in itself a skill, but a different one.