In English phonology, t-glottalization or t-glottaling is a sound change in certain English dialects and accents that causes the phoneme // to be pronounced as the glottal stop [ʔ] ( listen) in certain positions. It is never universal, especially in careful speech, and it most often alternates with other allophones of /t/ such as [t] (help·info), [tʰ], [tⁿ] (before a nasal), [tˡ] (before a lateral), or [ɾ].
As a sound change, it is a subtype of debuccalization. The pronunciation that it results in is called glottalization. Apparently, glottal reinforcement, which is quite common in English, is a stage preceding full replacement of the stop, and indeed, reinforcement and replacement can be in free variation.
The earliest mentions of the process are in Scotland during the 19th century, when Henry Sweet commented on the phenomenon. Peter Trudgill has argued that it began in Norfolk, based on studies of rural dialects of those born in the 1870s. The SED fieldworker Peter Wright found it in areas of Lancashire and said, "It is considered a lazy habit, but may have been in some dialects for hundreds of years." David Crystal claims that the sound can be heard in Received Pronunciation (RP) speakers from the early 20th century such as Daniel Jones, Bertrand Russell and Ellen Terry. The Cambridge English Pronouncing Dictionary claims that t-glottalization is now most common in London, Leeds, Edinburgh, and Glasgow.
Pre-glottalization of /t/ is found in RP and General American (GA) when the consonant /t/ occurs before another consonant, or before a pause:
The glottal closure overlaps with the consonant that it precedes, but the articulatory movements involved can usually only be observed by using laboratory instruments. In words such as 'eaten', 'button' pronounced with a glottal closure it is generally almost impossible to know whether the /t/ has been pronounced (e.g. [ˈiːʔtn̩], [ˈbʌʔtn̩]) or omitted (e.g. [ˈiːʔn̩], [ˈbʌʔn̩]).
In some accents of English, /t/ may be pre-glottalized intervocalically when it occurs finally in a stressed syllable. In the north-east of England and East Anglia pronunciations such as 'paper' [ˈpeɪʔpə], 'happy' [ˈhæʔpi] are found.
There is variation in the occurrence of glottalization within RP according to which consonant follows /t/: for example, some speakers do not glottalize /t/ when /r/ follows, in words such as 'petrol' /ˈpɛtrəl/, 'mattress' /ˈmætrəs/.
In RP, and in many accents such as Cockney as well as all American English, it is common for /t/ to be completely replaced by a glottal stop before another consonant, as in not now [nɒʔnaʊ] and department [dɪpʰɑː(ɹ)ʔmən̩t]. This replacement also happens before a syllabic //, as in button (representable as [ˈbʌʔn̩] or [ˈbʌʔɪ̈n]).
Among younger speakers of Britain, glottal replacement of /t/ is frequently heard in intervocalic position before an unstressed vowel:
Some British speakers even show glottal replacement in secondarily stressed syllables, though this is rarer:
In both RP and GA, /t/-replacement is found in absolute final position, though most commonly in younger people's speech.
T-glottalization is believed to have been spreading in Southern England at a faster rate than th-fronting. Cruttenden comments that "Use of [ʔ] for /t/ word-medially intervocalically, as in water, still remains stigmatised in GB." (GB is his alternative term for RP). The increased use of glottal stops within RP is believed to be an influence from Cockney and other working-class urban speech. In a 1985 publication on the speech of West Yorkshire, KM Petyt found that t-glottalization was spreading from Bradford (where it had been reported in traditional dialect) to Halifax and Huddersfield (where it had not been reported in traditional dialect). In 1999, Shorrocks noted the phenomenon amongst young people in Bolton, Greater Manchester: "It is not at all typical of the traditional vernacular, in contradistinction to some other varieties of English, but younger people use [ʔ] medially between vowels more than their elders."
Recent studies (Milroy, Milroy & Walshaw 1994, Fabricius 2000) have suggested that t-glottalization is increasing in RP speech. Prince Harry frequently glottalizes his t's. One study carried out by Anne Fabricius suggests that t-glottalization is increasing in RP, the reason for this being the dialect levelling of the Southeast. She has argued that a wave-like profile of t-glottalization has been going on through the regions, which has begun with speakers in London, due to the influence of Cockney. She says that this development is due to the population size of the capital, as well as London's dominance of the Southeast of England. However, Miroslav Ježek has argued that linguists attribute changes to London too readily, and that the evidence suggests that t-glottalization began in Scotland and worked its way down gradually to London.