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.
As a result of the obstruction of the airflow in the glottis, the glottal vibration either stops or becomes irregular with a low rate and sudden drop in intensity. 
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.
In the traditional Romanization of many languages, such as Arabic, the glottal stop is transcribed with an apostrophe, ⟨’⟩, which 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, ⟨ʻ⟩ (called ‘okina in Hawaiian and Samoan), which, confusingly, is used to transcribe the Arabic ayin as well 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 (Tagalog aso, "dog") is always pronounced with an unrepresented glottal stop before that vowel (as in Modern German and Hausa). Some orthographies use a hyphen instead of the reverse apostrophe if the glottal stop occurs in the middle of the word (Tagalog pag-ibig, "love"; or Visayan gabi-i, "night"). If 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 occur in the final vowel (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 (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. The numeral 7 is sometimes substituted for ʔ and is preferred in some languages such as Squamish.
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.
In English, the (phonemic) glottal stop occurs as an open juncture (for example, between the vowel sounds in uh-oh!,) and allophonically in T-glottalization. In British English, the glottal stop is most familiar in the Cockney pronunciation of "butter" as "bu'er". Additionally, there is the glottal stop as a null onset for English, in other words, it is the non-phonemic glottal stop occurring before isolated or initial vowels (for example, representing uh-oh!, [ˈʌʔoʊ] and [ˈʔʌʔoʊ] are phonemically identical to /ˈʌ.oʊ/).
Although this segment is not a written phoneme in English, it occurs 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: 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 (see stød), Chinese and Thai.
In many languages, the unstressed intervocalic allophone of the glottal stop is a creaky-voiced glottal approximant. It is known to be contrastive in only one language, Gimi, in which it is the voiced equivalent of the stop.
The table below 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.
|Abkhaz||аи||[ʔaj]||'no'||See Abkhaz phonology.|
|Arabic||Standard||أغاني||[ʔaˈɣaːniː]||'songs'||See Arabic phonology, Hamza.|
|Metropolitan||شقة||[ˈʃæʔʔæ]||'apartment'||Metropolitan dialects including Egyptian Arabic. Corresponds to /q/ in Literary Arabic.|
|Chechen||кхоъ / qo'||[qoʔ]||'three'|
|Chinese||Cantonese||愛/oi3||[ʔɔːi˧]||'love'||See Cantonese phonology.|
|Czech||používat||[poʔuʒiːvat]||'to use'||See Czech phonology.|
|Danish||hånd||[ˈhɒ̜̽nʔ]||'hand'||One of the possible realizations of stød. Depending on the dialect and style of speech, it can be instead realized as laryngealisation of the preceding sound. See Danish phonology.|
|Dutch||beamen||[bəʔˈaːmə(n)]||'to confirm'||See Dutch phonology.|
|Australian||cat||[kʰæʔ(t)]||'cat'||Allophone of /t/. See glottalization and English phonology.|
|RP and GA||button||[ˈbɐʔn̩] (help·info)||'button'|
|Esperanto||scii||[ˈst͡si.ʔi]||'to know'||See Esperanto phonology.|
|Finnish||linja-auto||[ˈlinjɑʔˌɑuto]||'bus'||See Finnish phonology.|
|German||Northern||Beamter||[bəˈʔamtɐ]||'civil servant'||See Standard German phonology.|
|Guaraní||avañe’ẽ||[ãʋ̃ãɲẽˈʔẽ]||'Guaraní'||Occurs only between vowels.|
|Hawaiian||ʻeleʻele||[ˈʔɛlɛˈʔɛlɛ]||'black'||See Hawaiian phonology.|
|Hebrew||מַאֲמָר||[maʔămar]||'article'||See Modern Hebrew phonology.|
|Icelandic||en||[ʔɛn]||'but'||Only used according to emphasis, never occurring in minimal pairs.|
|Iloko||nalab-ay||[nalabˈʔaj]||'bland tasting'||Hyphen when occurring within the word.|
|Indonesian||bakso||[ˌbäʔˈso]||'meatball'||Allophone of /k/ or /ɡ/ in the syllable coda.|
|Javanese||anak||[änäʔ]||'child'||Allophone of /k/ in morpheme-final position.|
|Korean||일||[ʔil]||'one'||In free variation with no glottal stop. Occurs only in initial position of word.|
|Malay||tidak||[ˈtidäʔ]||'no'||Allophone of final /k/ in the syllable coda, pronounced before consonants or at end of word.|
|Mutsun||tawka'li||[tawkaʔli]||'black gooseberry'||Ribes divaricatum|
|Nahuatl||tahtli||[taʔtɬi]||'father'||Often left unwritten.|
|Nez Perce||yáakaʔ||[ˈjaːkaʔ]||'black bear'|
|Nheengatu||ai||[aˈʔi]||'sloth'||Transcription (or absence thereof) varies.|
|Persian||معنی||[maʔni]||'meaning'||See Persian phonology.|
|Portuguese||Vernacular Brazilian||ê-ê||[ˌʔe̞ˈʔeː]||'yeah right'||Marginal sound. Does not occur after or before a consonant. In Brazilian casual speech, there is at least one [ʔ]–vowel length–pitch accent minimal pair (triply unusual, the ideophones short ih vs. long ih). See Portuguese phonology.|
|Some speakers||à aula||[ˈa ˈʔawlɐ]||'to the class'|
|Sardinian||Some dialects of Barbagia||unu pacu||[ˈuːnu paʔu]||'a little'||Intervocalic allophone of /n, k, l/.|
|Some dialects of Sarrabus||sa luna||[sa ʔuʔa]||'the moon'|
|Serbo-Croatian||и онда / i onda||[iː ʔô̞n̪d̪a̠]||'and then'||Optionally inserted between vowels across word boundaries. See Serbo-Croatian phonology|
|Spanish||Nicaraguan||más alto||[ˈma ˈʔal̻t̻o̞]||'higher'||Marginal sound or allophone of /s/ between vowels in different words. Does not occur after or before a consonant. See Spanish phonology.|
|Yucateco||cuatro años||[ˈkwatɾo̞ ˈʔãɲo̞s]||'four years'|
|Tagalog||oo||[oʔo]||'yes'||See Tagalog phonology.|
|Thai||อา||[ʔaː]||'uncle/aunt' (father's younger sibling)|
|Vietnamese||oi||[ʔɔj˧]||'sultry'||In free variation with no glottal stop. See Vietnamese phonology.|
|Võro||piniq||[ˈpinʲiʔ]||'dogs'||"q" is Võro plural marker (maa, kala, "land", "fish"; maaq, kalaq, "lands", "fishes").|
|Wagiman||jamh||[t̠ʲʌmʔ]||'to eat' (perf.)|
- Umeda N., "Occurrence of glottal stops in fluent speech", J. Acoust. Soc. Am., vol. 64, no. 1, 1978, pp. 88-94.
- Paul Morrow (March 16, 2011). "The basics of Filipino pronunciation: Part 2 of 3 • accent marks". Pilipino Express. Retrieved July 18, 2012.
- Ricardo M.D. Nolasco. Grammar notes on the national language (PDF).
- Joan Schoellner & Beverly D. Heinle, ed. (2007). Tagalog Reading Booklet (PDF). Simon & Schister's Pimsleur. pp. 5–6.
- "Proposal to add LATIN SMALL LETTER GLOTTAL STOP to the UCS" (PDF). 2005-08-10. Retrieved 2011-10-26.
- Browne, Rachel (12 March 2015). "What’s in a name? A Chipewyan’s battle over her native tongue". Maclean's. Retrieved 5 April 2015.
- Mastering Hebrew, 1988, ISBN 0812039904, p. xxviii
- Kortlandt, Frederik (1993). "General Linguistics & Indo-European Reconstruction" (PDF).
- Brown, Gillian. 1977:27. Listening to spoken English. London: Longman.
- Thelwall (1990:37)
- Watson (2002:17)
- Gussenhoven (1992:45)
- Sivertsen (1960:111)
- Roach (2004:240)
- Ladefoged (2005:139)
- Clark, Yallop & Fletcher (2007:105)
- Olson et al. (2010:206–207)
- Fonologia e Gramática do Nheengatu – A língua geral falada pelos povos Baré, Warekena e Baniwa Archived 2014-03-07 at the Wayback Machine. (in Portuguese)
- João Veloso & Pedro Tiago Martins (2013). O Arquivo Dialetal do CLUP: disponibilização on-line de um corpus dialetal do português (in Portuguese)
- Phonetic symbols for Portuguese phonetic transcription In European Portuguese, the "é é" interjection usually employs an epenthetic /i/, being pronounced [e̞ˈje̞] instead.
- It may be used mostly as a general call of attention for disapproval, disagreement or inconsistency, but also serves as a synonym of the multiuse expression "eu, hein!". (in Portuguese) How to say 'eu, hein' in English – Adir Ferreira Idiomas
- Blevins (1994:492)
- Su sardu limba de Sardigna et limba de Europa, Lucia Grimaldi & Guido Mensching, 2004, CUEC, pp.110-111
- Landau et al. (1999:67)
- The hypo-hyperarticulation continuum in Nicaraguan Spanish
- Voiceless stop aspiration in Yucatán Spanish: a sociolinguistic analysis
- Thompson (1959:458–461)
- Blevins, Juliette (1994), "The Bimoraic Foot in Rotuman Phonology and Morphology", Oceanic Linguistics, 33 (2): 491–516, JSTOR 3623138, doi:10.2307/3623138
- Clark, John Ellery; Yallop, Colin; Fletcher, Janet (2007), An introduction to Phonetics and Phonology, Wiley-Blackwell
- Gussenhoven, Carlos (1992), "Dutch", Journal of the International Phonetic Association, 22 (2): 45–47, doi:10.1017/S002510030000459X
- Ladefoged, Peter (2005), Vowels and Consonants (Second ed.), Blackwell, ISBN 0-631-21411-9
- Landau, Ernestina; Lončarić, Mijo; Horga, Damir; Škarić, Ivo (1999), "Croatian", Handbook of the International Phonetic Association: A guide to the use of the International Phonetic Alphabet, Cambridge: Cambridge University Press, pp. 66–69, ISBN 0-521-65236-7
- Olson, Kenneth; Mielke, Jeff; Sanicas-Daguman, Josephine; Pebley, Carol Jean; Paterson, Hugh J., III (2010), "The phonetic status of the (inter)dental approximant", Journal of the International Phonetic Association, 40 (2): 199–215, doi:10.1017/S0025100309990296
- Roach, Peter (2004), "British English: Received Pronunciation", Journal of the International Phonetic Association, 34 (2): 239–245, doi:10.1017/S0025100304001768
- Schane, Sanford A (1968), French Phonology and Morphology, Boston, Mass.: M.I.T. Press, ISBN 0-262-19040-0
- Sivertsen, Eva (1960), Cockney Phonology, Oslo: University of Oslo
- Thelwall, Robin (1990), "Illustrations of the IPA: Arabic", Journal of the International Phonetic Association, 20 (2): 37–41, doi:10.1017/S0025100300004266
- Thompson, Laurence (1959), "Saigon phonemics", Language, 35 (3): 454–476, JSTOR 411232, doi:10.2307/411232
- Watson, Janet (2002), The Phonology and Morphology of Arabic, New York: Oxford University Press, ISBN 0-19-824137-2
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