Skip to Content

Department of Linguistics

PHONETICS AND PHONOLOGY

Pulmonic Airflow

Robert Mannell


A simplified diagram of the vocal tract showing the energy generation function of the lungs. Above the vocal folds are the various cavities that can be modified in size and shape to cause changes in the sound quality of the speech sounds.

Expanding the thoracic cavity by expanding the rib cage (raising the ribs) and by lowering the diaphragm increases lung volume, decreases air pressure in the lungs and so air is drawn in from the from the outside to equalise pressure. Contracting the thoracic cavity by contracting the rib cage (lowering the ribs) and by raising the diaphragm decreases lung volume, increases air pressure in the lungs and so air is expelled from the lungs to equalise pressure with the outside air.