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 (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 or. (In some typefaces, the apostrophe will occur above the m.)