ABSTRACT
In Chapter 1 we discussed the structures that make up the vocal tract, and pointed briefly to some of their functions as adapted for speech. For speech to occur, however, we must have a moving body of air through the vocal tract, or part of the vocal tract. Sound waves are created by modifying this moving body of air: the modifications being caused by the movements of various vocal organs, singly or in combination. What do we need to do to create this moving airstream? A variety of devices can cause air to flow: for example, a bellows-like pump can draw air in and then push it out creating an alternate inward and outward airflow. Also, a piston travelling up and down within its casing draws air alternately upwards and downwards.
