The document discusses different types of airstream mechanisms in speech production. It describes the three main types as pulmonic, glottalic, and velaric initiation. Pulmonic initiation uses the lungs to push air out (egressive) or pull air in (ingressive). Most sounds are egressive pulmonic. Glottalic initiation uses the vocal cords to eject air (ejectives) or pull air in (implosives). Velaric initiation uses tongue movement to create clicks by pulling air in. The document provides examples of consonants produced by each airstream mechanism and discusses their voiced or voiceless nature.