The glottal stop is a type of consonantal sound used in many spoken languages, produced by obstructing airflow in the vocal tract or, more precisely, the glottis. The symbol in the International Phonetic Alphabet that represents this sound is ⟨ʔ⟩. Using IPA, this sound is known as a glottal plosive.
In English, the glottal stop occurs as an open juncture (for example, between the vowel sounds in uh-oh!, in "grade A" as opposed to "gray day",) and in T-glottalization. For most US English speakers, a glottal stop is used as an allophone of /t/ between a vowel and "m" (as in atmosphere or Batman) or a syllabic "n" (as in button or mountain) except in slow speech. In British English, the glottal stop is most familiar in the Cockney pronunciation of "butter" as "bu'er".
Features of the glottal stop:Its manner of articulation is occlusive, which means it is produced by obstructing airflow in the vocal tract. Since the consonant is also oral, with no nasal outlet, the airflow is blocked entirely, and the consonant is a stop.
Its phonation is voiceless, which means it is produced without vibration of the vocal cords; necessarily so, because the vocal cords are held tightly together, preventing vibration.
It is an oral consonant, which means air is allowed to escape through the mouth only.
Because the sound is not produced with airflow over the tongue, the central–lateral dichotomy does not apply.
The airstream mechanism is pulmonic, which means it is articulated by pushing air solely with the lungs and diaphragm, as in most sounds.
Although this segment is not a written phoneme in English, it is present phonetically in nearly all dialects of English as an allophone of /t/ in the syllable coda. Speakers of Cockney, Scottish English and several other British dialects also pronounce an intervocalic /t/ between vowels as in city. In Received Pronunciation, a glottal stop is inserted before a tautosyllabic voiceless stop, e.g. sto’p, tha’t, kno’ck, wa’tch, also lea’p, soa’k, hel’p, pin’ch.
In many languages that do not allow a sequence of vowels, such as Persian, the glottal stop may be used to break up such a hiatus. There are intricate interactions between falling tone and the glottal stop in the histories of such languages as Danish (cf. stød), Chinese and Thai.
In many languages, the unstressed intervocalic allophone of the glottal stop is a creaky-voiced glottal approximant. These are only known to be contrastive in one language, Gimi, where it is the voiced equivalent of the stop.
In the traditional Romanization of many languages, such as Arabic, the glottal stop is transcribed with an apostrophe, ⟨’⟩, and this is the source of the IPA character ⟨ʔ⟩. In many Polynesian languages that use the Latin alphabet, however, the glottal stop is written with a reversed apostrophe, ⟨‘⟩ (called ‘okina in Hawaiian and Samoan), which, confusingly, is also used to transcribe the Arabic ayin and is the source of the IPA character for the voiced pharyngeal fricative ⟨ʕ⟩. In Malay the glottal stop is represented by the letter ⟨k⟩, in Võro and Maltese by ⟨q⟩.
Other scripts also have letters used for representing the glottal stop, such as the Hebrew letter aleph ⟨א⟩, and the Cyrillic letter palochka ⟨Ӏ⟩ used in several Caucasian languages. In Tundra Nenets it is represented by the letters apostrophe ⟨ʼ⟩ and double apostrophe ⟨ˮ⟩. In Japanese, glottal stops occur at the end of interjections of surprise or anger, and are represented by the character ⟨っ⟩.
In the graphic representation of most Philippine languages, the glottal stop has no consistent symbolization. In most cases, however, a word that begins with a vowel-letter (e.g. Tagalog aso, "dog") is always pronounced with an unrepresented glottal stop before that vowel (as also in Modern German and Hausa). Some orthographies employ a hyphen, instead of the reverse apostrophe, if the glottal stop occurs in the middle of the word (e.g. Tagalog pag-ibig, "love"; or Visayan gabi-i, "night"). When it occurs in the end of a Tagalog word, the last vowel is written with a circumflex accent (known as the pakupyâ), if both a stress and a glottal stop occurs at the final vowel (e.g. basâ, "wet"); or a grave accent (known as the paiwà), if the glottal stop occurs at the final vowel, but the stress occurs at the penultimate syllable (e.g. batà, "child").
Some Canadian indigenous languages have adopted the phonetic symbol "ʔ" itself as part of their orthographies. In some of them, it occurs as a pair of uppercase and lowercase characters, Ɂ and ɂ. Sometimes the number symbol 7 is used if the ʔ character is not available to the typesetter, and in some cases such as in the Squamish language, the 7 has become the preferred symbol.
In 2015, two women in the Northwest Territories challenged the territorial government over its refusal to permit them to use the ʔ character in their daughters' names: Sahaiʔa, a Chipewyan name, and Sakaeʔah, a Slavey name (the two names are actually cognates). The territory argued that territorial and federal identity documents were unable to accommodate the character. The women registered the names with hyphens instead of the ʔ, while continuing to challenge the policy.
Use of the glottal stop is a distinct characteristic of the Southern Mainland Argyll dialects of Scottish Gaelic. In such a dialect, the standard Gaelic phrase Tha Gàidhlig agam (I speak Gaelic), would be rendered Tha Gàidhlig a'am.
This table demonstrates how widely the sound of glottal stop is found among the world's spoken languages. It is not intended to be a complete list. Any of these languages may have varieties not represented in the table.