Retroflex click

The retroflex clicks are a family of click consonants known only from the Central ǃKung language or dialect of Namibia. They are sub-apical retroflex and should not be confused with the more widespread postalveolar clicks, which have also been called "retroflex" due to their concave tongue shape and sometimes apical-retroflex articulation.
The 'implicit' symbol in the International Phonetic Alphabet that represents the forward articulation of these sounds is. However, usage is rare. In the literature, retroflex clicks are typically written with the ad hoc digraph, the convention since Doke identified them as retroflex in 1925.
Retroflex clicks are extraordinarily rare. True retroflex clicks occur in at least some dialects of Central ǃKung. They are reconstructed for the Proto-Kxʼa language and tentatively for Proto-Khoe–Kwadi.
A nasal retroflex click is reported from Damin.

Retroflex click consonants and their transcription

Basic retroflex clicks in three common transcription conventions are:

Features of postalveolar clicks:

The place of articulation is post-alveolar, and the tongue shape may be subapical, which means it is articulated with the tip of the tongue curled up. The center of the tongue moves downward to create suction.

As with other click articulations, retroflex clicks may be produced with various manners. An example is the voiced retroflex click in the Grootfontein ǃKung word for 'water', .
Damin is the only other language known to have had such a sound, though only the nasal click occurred. It occurred as both a single and a doubled consonant, which was articulated twice. It was apico-domal, and no comparison was ever done with the Central Juu articulation.
A retroflex series claimed for Ekoka ǃKung turns out to be domed palatal clicks.