I’d say just act like they aren’t stuttering. As in, if you were arranging papers as students asked you questions before, continue to do so. If you were making eye contact, continue. Another thing is, I don’t know if this is usual, but I stutter more when I think people aren’t listening to me so keep that in mind as well. Sorry if those two things sound contradictory, they are, but stuttering is confusing. Basically let them know you’re listening but don’t make a big deal out of it. And lastly, don’t interrupt! Thank you for caring, people like you mean the world to me.