Punch players have traditionally used a device to change their voices into the shrill screech that has long been the signature sound of the little hellion. The device is called a swazzle and at a glance looks a bit like a bird call or some type of cheese slicer. It is actually a reed held in a contoured frame that fits the inside of the mouth. It is held between the roof of the mouth and the center of the tongue. Speaking through it causes the reed to vibrate and alter the performers voice. The following drawing is intended to be a visual explanation of the device due to the fact that it so closely resembles several semi-musical, or bird call-like devices. Some performers in an attempt to soften sharp corners - and prevent swallowing the swazzle - wrap the entire perimeter in string. The end is then left to dangle from the mouth as a safety measure.

My drawing of a swazzle, saved at the Punch Page