All click types (alveolar ǃ, dental ǀ, lateral ǁ, palatal ǂ, retroflex ‼, and labial ʘ) have linguo-glottalic variants, which occur as both stops and affricates, and may be voiced.
Phonetically, a linguo-glottalic consonant is a click in which the forward and rear articulations are released independently.
The forward articulation, made with the lips or the front of the tongue, releases with a lingual airstream as in any click.
In Juǀ’hõa, for example, they are written voiceless ǃk ǁk ǀk ǂk and voiced gǃk gǁk gǀk gǂk, and in the old orthography qg’ xg’ cg’ çg’ and dqg’ dxg’ dcg’ dçg’; in Naro, they are (voiceless) qg’ xg’ cg’ tcg’, and in Khoekhoe (Korana), ǃkh’ ǁkh’ ǀkh’ ǂkh’.
Although no language contrasts these possibilities from homorganic affricates, she holds that they are different enough in sound that considering them to be different consonants is useful.
[2] (It is not clear if the ⟨k⟩ is written because the rear release is actually an affricate, or because it better distinguishes these from the homorganic/uvular case, as in broad transcription ⟨x⟩ may be used for either a velar or a uvular fricative.)