How is the Avox girl punished?

The Avox girl, whose name is Lavinia, is first encountered by Katniss when she's out hunting with Gale in the off-limits wild forest outside District 12. Lavinia is with a boy, and they seem to be escaping from the Capitol. Soon a gigantic Capitol hovercraft descends, firing a spear at the boy, which kills him instantly. Lavinia, on the other hand, is scooped up and taken away.
As punishment for her unspecified transgression, the girl has her tongue cut out. This turns her into an Avox, someone punished for rebelling against the state. Lavinia, like all Avoxes, is little better than a slave, forced to work in a positions of menial subservience. Her punishment is hugely symbolic, because now that she has no tongue, she cannot speak. Both literally and figuratively speaking, she has no voice in this society.