The source of air for SPEECH SOUNDS

 The source of air for SPEECH SOUNDS

The LUNGS (Fig. 1) are basically sponge-like in design, except that they hold air (in a myriad of tiny airsacs), not water. When we breathe in, we enlarge the chest cavity (in part by lowering the diaphragm). This in turn expands the lungs, and air rushes in to fill the vacuum. Breathing out involves the opposite procedure. The chest is contracted and air is squeezed out of the lungs, passing through the two BRONCHI (or bronchial tubes), then through the windpipe (more technically the TRACHEA), and finally emerging in the throat.
First, we normally speak only while breathing out. It’s also quite possible to speak while breathing in (for example when counting and not wishing to pause to draw breath), but this is an inefficient way of making sounds and therefore not a regular feature of any language. In some speech-communities, though, people use “ingressive air” as a conventional means of disguising their voices.
Second, there are various ways of making speech sounds with air that doesn’t originate in the lungs. The disapproving noise conventionally represented as tut tut! is an example. Some languages make regular use of “click” sounds like this one, as well as other “non-pulmonic” sounds that from a European point of view seem even more exotic.
Third, if we used the same breathing rhythm for talking as for just breathing quietly, we’d have to pause for breath every couple of words. (Try it and see.) In speech, quite complex adjustments of the chest muscles and diaphragm are constantly being made in order to slow down the airstream and hold it back as it leaves the lungs.