I have a group of 12th grade students that just won't stop talking. I feel like I have tried everything and yet they still won't listen. I have tried positive reinforcement, enforcing punishment, and even ignoring it at times. What haven't I tried yet? I have no idea what to do next.
Singling out the ring leader is always a great first step to stop misbehavior in the classroom that involves several students. If you pick them out then other will probably quiet down in no time.
That age is a bit tricky. But, you could sit the student in close proximity with you. Try including them in the lesson. If you are familiar with what they do, begin to include the students in the learning process. You could also give them responsible assignments that will engage them in conversations with other students (maybe leadership roles or something so that you are not constently talking to them).