Just know that you don't have to beat around the bush when inquiring about the wait. You shouldn't state a demand of when you want to know by, but it's perfectly okay to ask something along the lines of, "Do you have an idea of when I can expect to hear back?" Or, "How far along are you in the process of filling this position?" Or, even, "Is there a date when I should follow-up?" Many interviewers will tell you this themselves, but if someone forgets, it's okay to ask for a prompt.