II. WHAT IS SPEECH?
§ 24. To follow the history of the sounds in any language we must understand how sounds are produced.
Just as in a whistle or an organ sound is made by a current of air passing through certain openings, and being set in vibration by certain tongues or edges put in the way of the current, so sound is produced in the human throat and mouth by a current of air sent out from the lungs; and different kinds of sound arise from the different ways in which the current is treated as it passes through the throat and mouth.
Breath and Voice
§ 25. In the larynx (that is, the upper end of the wind-pipe) through which the current passes, there are two wonderful pieces of soft muscle, which can be either left loose, in which case they fold themselves up against the wall of the larynx on either side, and do not affect the current of air at all; or stretched tightly, so that the current has to pass between two crisp, straight, and almost parallel edges (but not quite parallel since they meet at one end). These are
