"Warum brauche ich eine Erlaubnis?"
Übersetzung:Why do I need permission?
Good question. It depends on what the Germain word 'Erlaubnis' means precisely (and my German isn't good enough to help). I can tell you the difference in English (roughly). A permit is more precise than permission. You need a permit to drive: an official statement to that effect.
In school children need permission to go to the bathroom, but it does not usually require a permit. A permit suggests that the government gave permission. The permission might be formalized through a piece of paper called a 'permission slip' though.