The function of the soft palate is to provide at the pharyngeal crossroad of airway and foodway a mobile separation between the nasal and the oral passage. In respiration through the nose the air can pass freely between the soft palate and the pharyngeal wall, while in swallowing the soft palate closes off this passage so that no food or drink may reach the nose.
In addition to this function the soft palate contributes to the faculty of speech as developed in the human race. The lowering of the larynx below the oral level in the evolution of biped man entails not only mouth breathing but also oral speech. (cf. Negus: "The larynx is pushed down the throat as posture became erect!") In various animals (horse, dog, etc.) in which the larynx is situated more in line with the oral cavity or even higher (in the nasopharynx), mouth breathing and