This article is about the sound in spoken language. For the letter, see glottal stop (letter).The glottal stop, or more fully, the voiceless glottal plosive, is a type of consonantal sound which is used in many spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is ?. The glottal stop is the sound made when the vocal cords (vocal folds) are (1) drawn together by muscular action to interrupt the flow of air being expelled from the lungs and then (2) released as pressure builds up below them; for example, the break separating the syllables of the interjection uh-oh. Strictly, the perception that it is a consonantal sound is produced by the release; the closure phase is necessarily silent because during it there is no airflow and the vocal cords are immobilized. It is called the glottal stop because the technical term for the gap between the vocal cords, which is closed up in the production of this sound, is the glottis. The term "glottal stop" is one of rather few technical terms of linguistics which have become well known outside the specialism.
While this segment is not a phoneme in English, it is present phonetically in nearly all dialects of English as an allophone of /t/. Most British English speakers will use it for the first "t" in fortnight, where a consonant follows immediately; speakers of Cockney and many other dialects will also use it for the "t" between vowels in city. It is variably present at word boundaries where a vowel follows at the beginning of the next word, as with the final "t" of "sort" in sort of.
Another common usage of the glottal stop as an allophone to 't' more commonly found in North America is in the environment in which the 't' is immediately followed by a non-syllabic 'n' sound, as in mutant or important.
