Glottalization
Glottalization is the complete or partial closure of the glottis during the articulation of another sound. Glottalization of vowels and other sonorants is most often realized as creaky voice. Glottalization of obstruent consonants usually involves complete closure of the glottis; another way to describe this phenomenon is to say that a glottal stop is made simultaneously with another consonant. In certain cases, the glottal stop can even wholly replace the voiceless consonant. The term 'glottalized' is also used for ejective and implosive consonants; see glottalic consonant for examples.
Most often, glottalization is transcribed with a superscript glottal stop . There are two other ways to represent glottalization of sonorants in the IPA: the same way as ejectives, with an apostrophe; or with the under-tilde for creaky voice. For example, the Yapese word for "sick" with a glottalized m could be transcribed as either or.
Types
Glottalization varies along three parameters, all of which are continuums. The degree of glottalization varies from none through stiff voice and creaky voice to full glottal closure. The timing also varies, from a simultaneous single segment to an onset or coda such as or to a sequence such as or. Full or partial closure of the glottis also allows glottalic airstream mechanisms to operate, producing ejective or implosive consonants; implosives may themselves have modal, stiff, or creaky voice. It is not always clear from linguistic descriptions if a language has a series of light ejectives or voiceless consonants with glottal reinforcement, or similarly if it has a series of light implosives or voiced consonants with glottal reinforcement. The airstream parameter is only known to be relevant to obstruents, but the first two are involved with both obstruents and sonorants, including vowels.Glottal replacement
Glottal replacement, or glottaling, is when a phoneme is completely substituted by a glottal stop. This is very common in British English dialects such as Cockney and Estuary English. In those dialects, the glottal stop is an allophone of, and word-finally and when followed by an unstressed vowel in a post-stress syllable. 'Water' can be pronounced – the glottal stop has superseded the 't' sound. Other examples include "city", "bottle", "Britain", "seniority". In some consonant clusters, glottal replacement of is common even among speakers of RP.Geordie English has a unique form of glottalization involving glottal reinforcement of, and, for example in "happy", "matter" and "lucky". Those sounds between vowels are pronounced simultaneously with a glottal stop represented in IPA as ⟨⟩, ⟨⟩ and ⟨⟩⟩.
Glottal replacement occurs in Indonesian in which syllable final is produced as a glottal stop. In all Gorontalic languages except Buol and Kaidipang, *k was replaced by a glottal stop, even word-initially, except when it followed *ŋ. In Hawaiian, the glottal stop is reconstructed to have come from other Proto-Polynesian consonants. The following table displays the shift →, as well as the one → :
| Gloss | man | sea | taboo | octopus | canoe |
| Tongan | |||||
| Samoan | |||||
| Māori | |||||
| Rapanui | |||||
| Rarotongan | |||||
| Hawaiian |
Glottal replacement is not purely a feature of consonants. Yaneshaʼ has three vowel qualities that have phonemic contrasts between short, long, and "laryngeal" or glottalized forms. While the latter generally consists of creaky phonation, there is some allophony involved. In pre-final contexts, a variation occurs ranging from creaky phonation throughout the vowel to a sequence of a vowel, glottal stop, and a slightly rearticulated vowel: →.