All click types (alveolar ǃ, dental ǀ, lateral ǁ, palatal ǂ, retroflex ‼, and labial ʘ) have glottalized variants.
In Khoekhoe they are written with the single letters ǃ ǁ ǀ ǂ, in Juǀ’hõa, as ǃ’ ǁ’ ǀ’ ǂ’ with a preceding nasal vowel, in Sandawe as q’ x’ c’, in Hadza as qq xx cc, and in Xhosa as nkc nkx nkq.
In many languages, however, the glottal closure is not complete, in which case they are pronounced with accompanying voiceless nasal airflow and transcribed ⟨ŋ̊!ʔ⟩, etc.
A more general transcription is ⟨ᵑ!ˀ⟩; superscripting the nasal and glottal components indicates that they are articulated simultaneously with the click and not adjacent to it.
In canonical form, a glottal stop occurs between the release of the click and the start of the following vowel.
In a few languages—Gǀui, Taa, ǂ’Amkoe, and, in Miller's analysis, Yeyi—there is in addition a series of oral, non-contour glottalized clicks.
These are pronounced like ordinary voiced nasal clicks, but are preceded by a very short period of prenasalization that has a glottal-stop onset.