At the opposite extreme, the cords can be drawn tightly together so that no air can pass. This produces ‘glottal catch’, […]. In English we often begin an emphatic exclamation such as ‘ouch!’ with a glottal catch, though phonemically the utterance begins with a vowel (/áwč/). In many languages glottal catches occur frequently and in phonemic contrast to other types of articulation.
- Hockett (1958), Pag. 65