Journey along the vocal tract
Fundamental physiological processes like those mentioned above (eating, breathing, etc.) take place simultaneously or alternatively with the production of speech sounds. We can hardly think of speaking as being separated from the activity of breathing, as the air that is breathed in and out of the lungs has a crucial role in the process of uttering sounds. Just read i.e. this last passage out loud and pay attention to the airstream floating out of your mouth or the moment of your breathing in.
You surely realize that breathing is a rhythmic process including two successive stages: inspiration and expiration. The majority of sounds used in most languages are produced with air that is pushed up from the lungs through the windpipe, or trachea, and leaves the body through the mouth and sometimes through the nose. Because we speak while we expel the air from our lungs, the sounds that we produce are called egressive and the movement of air is called an egressive pulmonic air-stream (egressive "outwards", pulmonic "of the lungs"). Virtually all English sounds are produced by such an egressive pulmonic air-stream mechanism.
The lungs then can be said to be the starting point of our journey along the vocal tract. In order to speak you need air and this air, being pushed out of your lungs, can be manipulated at various places and in various ways to form different sounds. The next station on the air's way up from the lungs through the trachea is the place where the production of sounds really starts: the larynx.
Move on to Journey along the vocal tract Page 2