Very nosy neighbors

I am about to go back to college. I do everything via dictation. My roommate, my neighbor, and his friends are total pot heads with nothing better to do then be in my business. They are always listening to my dictation confused. What is a nice way to say back off and respect the fact that this dictation is private and is being used to better a field I am studying to be applied in a job. Like I’ve had it with their nosy mess. The walls are thin and all of them stay home and just get high. I speak three languages as well. I don’t know how to tell them nicely to stay out of my business!!!!!