As teacher of writing, I've already come across multiple situations where a student has used AI to help create an assignment. As I read students' essays and other writing assignments, there are times when there's just a certain sixth sense that says, "This is not human writing." It's very subtle, but the sense of non-humanness is definitely there. 

I found this article on the topic by Miriam Bowers-Abbott and Wyatt Abbott illuminating. Here's an excerpt:

 Connectives are a large group of terms inclusive of conjunctions (such as and), prepositions (such as before), and adverbs (such as however). There is a precedent for using such terms as a means to distinguish the backgrounds of language users, often as a means to differentiate between native speakers (NS) and non-native speakers (NNS) of a language. In a comparison of student English essays by NS and NNS of French origin, Granger and Tyson (1996) found that NNS were far less likely to use a term such as “instead” in their writing. At the same time, the researchers found that NNS used a term such as “indeed” at nearly four times the frequency of NS. Ma and Wang (2016) compared essays written in English by British and American students to essays written in English by Cantonese students. In the study, researchers noted many similarities in connective usage, but also noted that NS used the term “because” with higher frequency. Kuswoyo et al. (2020) compared language usage in NS and NNS of English among engineering lecturers. The researchers found that the NNS tended to use “and” and “so” more frequently than NS in lectures.