Anatomy and Physiology

One of the functions of respiration is powering of the speech production mechanism. It provides energy source for oral communication. When the volume of the chest cavity increases/expands, air is inhaled into the lungs by the way of either the mouth or nose and trachea. An increase in the volume of the chest may be affected through a downward, contracting movement of the diaphragm; through an upward, outward movement of the lower ribs; or …

…is closing of the vocal folds under constant muscle tension, with temporarily decreased air pressure at the glottis “sucking” the folds back together. The vocal folds adduct back together because of elastic recoil. As you finish saying the utterance, the thorax size reduces and that results in a positive pressure within the alveoli. There may be intonation while saying this utterance. One may end it with a falling intonation, and put more stress on speech.