The physics and physiology of speech
Humans are able to produce sounds of speech with special vocal organs. In science there are very detailed understandings of how the human body produces the sounds of speech. We use our lungs to breathe out air, which produces vibrations in the larynx and then we utilize our tongue, teeth and lips to modify the sounds. The diagram below shows some of the more important speech organs.
The diagram is a simplified cross-section through the human head.
The following picture shows some varying tongue positions, we use to produce phones.