In phonetics, the airstream mechanism is the method by which airflow is created in the vocal tract. Along with phonation and articulation, it is one of three main components of speech production. The airstream mechanism is mandatory for most sound production and constitutes the first part of this process, which is called initiation.

The organ generating the airstream is called the initiator and there are three initiators used phonemically in non-disordered human oral languages:

• the diaphragm together with the ribs and lungs (pulmonic mechanisms),
• the glottis (glottalic mechanisms), and
• the tongue (lingual or "velaric" mechanisms).

Though not used in any language, the cheeks may be used to generate the airstream (buccal mechanism, notated {ↀ} in VoQS). See buccal speech.

After a laryngectomy, the esophagus may be used as the initiator (notated {Œ} for simple esophageal speech and {Ю} for tracheo-esophageal speech in VoQS). See esophageal speech.

Percussive consonants are produced without any airstream mechanism.