What do you say to parents about their misbehaving daughters?

I teach 10th grade, and am in my 2nd year of teaching. I am having a tough time with a few disrespectful teenage girls who will not stop talking and keep disrupting the cl. School policy states to first verbally warn the students on at least 2 occions, which I have done. Before any school discipline or punishment can be doled out, parentals contact in the form of a phone call must be made. I have 8 differents girls whose parents I need to call. Experienced teachers, what exactly should I say?