Glottalisation

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 (partial closure). 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.

There are two other ways to represent glottalization of sonorants in the IPA: (a) the same way as ejectives, with an apostrophe; or (b) with the under-tilde for creaky voice. For example, the Yapese word for "sick" with a glottalized m could be transcribed as either [mʼaar] or [m̰aar]. (In some typefaces, the apostrophe will occur above the m.)

Glottalization varies along three parameters, all of which are continuums. The degree of glottalization varies from none (modal voice, [d]) through stiff voice ([d̬]) and creaky voice ([d̰]) to full glottal closure (glottal reinforcement or glottal replacement, described below). The timing also varies, from a simultaneous single segment [d̰] to an onset or coda such as [ˀd] or [dˀ] to a sequence such as [ʔd] or [dʔ]. 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.

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