The glottal stop or voiceless glottal plosive is a type of consonantal sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is ʔ, and the equivalent X-SAMPA symbol is ?. The glottal stop is the sound made when the vocal cords are pressed together, and is the sound in the middle of the interjection uh-oh. In many dialects of English, glottal stop is an allophone of /t/ in final position, such as the "t" in habit or pat. In some dialects, eg. Cockney, glottal stop is also an allophone of /t/ in medial position, such as in the word bottle or fatter. In other languages, it is a full phoneme. In these cases, it is sometimes written as an opening single quote ‘, as in Hawai‘ian, where it is called ‘okina. Maltese uses the letter q to denote the sound. Other examples of language using phonemic glottal stop are Nahuatl and many other Native American languages, Samoan, Hebrew, Arabic, and Japanese. In German and Dutch, glottal stop is not phonemic, but it is inserted in multi-morphemic words before morphemes that begin with a vowel, such as German Beamter (="civil servant") or Dutch beamen (="to endorse"), where the glottal stop is inserted after the prefix "be-".

{| border="1" cellspacing="0" cellpadding="4" style="float:right; margin-left:15px" | IPA - Unicode | align="center" style="font-size: 24px"|ʔ |- | IPA - image | |- | X-SAMPA | align="center"|? |- | Kirshenbaum | align="center"|? |- ! colspan="2"|Sound sample |}

Features of this consonant:

• Its manner of articulation is plosive or stop, which means it is produced by obstructing airflow in the vocal tract.
• Its place of articulation is glottal which means it is articulated by the vocal folds.
• Its phonation type is voiceless, which means it is produced without vibrations of the vocal cords.
• It is an oral consonant, which means air is allowed to escape through the mouth.
• It is a central consonant, which means it is produced by allowing the airstream to flow over the center of the tongue, rather than the sides.
• The airstream mechanism is pulmonic egressive, which means it is articulated by pushing air out of the lungs and through the vocal tract, rather than from the glottis or the mouth.

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