When twanging, the opening of the epiglottic funnel is made smaller by bringing the arytenoid cartilages closer to the lower part of epiglottis (the petiole).
When the opening of the funnel is made EVEN smaller by bringing the epiglottis closer to the arytenoid cartilages, the sound assumes a much sharper and more penetrating, snarling character, like a cackle. This is known as Distinct twang. The more squeezed the funnel, the more snarling the sound.
Distinct twang is used, for example, in the stereotypical American way of speaking (the Southern accent) and often in country music. It is often mistaken for nasality but has nothing to do with it. In twang, the sound may come through the mouth and/or through the nose.