The document describes the production of speech sounds in the vocal tract. It identifies the main articulators involved in producing vowels and consonants, including the larynx, vocal tract, tongue, lips, teeth, hard palate, soft palate, and nasal cavity. Vowels are produced with an unobstructed air flow through the vocal tract, while consonants involve obstructing the air flow in some way using the articulators. The position and shape of the tongue and lips can be varied to produce different speech sounds.