Strident vowels (also called sphincteric vowels) are strongly pharyngealized vowels accompanied by (ary)epiglottal trill, where the larynx is raised and the pharynx constricted, so that either the epiglottis or the arytenoid cartilages vibrate instead of the vocal cords. Strident vowels are fairly common in Khoisan languages, where they contrast w...