Subglottal and Laryngeal Vocal Tract


The subglottal vocal tract refers to the collective of the structures below the glottis (Zsiga, p. 6, 2013). A brief definition of the structure within the subglottal system can be found below the following diagram:

Source: Philip Rubin and Eric Vatikiotis-Bateson, Haskins Laboratories
  • Larynx: The set of cartilages that are responsible for protecting and manipulating the position of the vocal folds (located within the larynx) is referred to as the larynx. (Zsiga, p. 7, 2013).
    • Vocal Folds: The vocal folds are a set of two flaps made of tissue inside the trachea. During speech production, the vocal folds can be manipulated to alter vibration rates. When the vocal folds vibrate at a faster rate, the pitch of speech will be higher. Conversely, when vocal folds vibrate slower, the pitch will be lower. The process of vocal folds vibrating during speech production is referred to as voicing (Zsiga, p. 7-8, 2013).
  • Trachea: The trachea is commonly referred to as the “windpipe.” The trachea is a tube-like structure made of different cartilages and connects the mouth and lungs (Zsiga, p. 7, 2013).
  • Lungs: In speech, the lungs power the air movement used during sound production. This is referred to as the pulmonic airstream mechanism (Zsiga, p. 7, 2013).
  • Diaphragm: The diaphragm is the largest muscle used during speech. The diaphragm is the muscle which allows the lungs to enlarge, and thus intaking air (breathing in). When the diaphragm contracts, the lungs open, and when the diaphragm relaxes, the lungs force the air out of the trachea and then the nose (Zsiga, p. 7, 2013).