We
can mention the subject you when it contrasts with another
person.
I'll wait
here. You go round the back.
You can also make an order emphatic or even
aggressive.
You be careful what you're saying.
NOTE
A
few other phrases can be the subject.
All of
you sit down! Everyone stop
what you're doing.
The
negative don't comes before the subject. Don't
you talk to me like that.