They cannot. Unfortunately many believe they can, and it is impossible to disprove. So now real people need to write avoiding certain styles, because a lot of other people have decided those are "LLM clues." Bullets, EM Dash, certain common English phases or words (e.g. Delve, Vibrant, Additionally, etc)[0]. Basicaly you need to sprinkle subtle mistakes, or lower the quality of your written communications to avoid ac…
Someone with native fluency in American English can (should) be able to tell the difference between human writing and unpolished AI copy-paste. Essentially 0 people use emoji to create a bulleted list. Nobody unintentionally cites fake legal precedents or non-existent events, articles, or papers. Even the “it’s not X, it’s Y” structure, in the presence of other suspicious style/tone cues signals LLM text.
I haven't seen this yet, but I guess the only reason I haven't done it is because it never crossed my mind.
What I have found an easy detection is non-breaking spaces. They tend to get littered through the passages of text without reason.