|Voiced retroflex click|
|Retroflex nasal click|
The retroflex clicks are a family of click consonants known only from the Central !Kung dialects of Namibia and the Damin ritual jargon of Australia. They may be sub-apical retroflex and should not be confused with the more widespread postalveolar clicks, which are sometimes called retroflex.
There is no symbol in the International Phonetic Alphabet that represents the forward articulation of these sounds, but one may be derived with a rhotic diacritic from the alveolar click: ǃ˞. In the literature they are typically written with the ad hoc digraph ⟨‼⟩, the convention since Doke first described them in 1926. (Doke's proposed symbol, resembling ⟨ψ⟩ (or more precisely an inverted ⟨⋔⟩, descender only), did not catch on. A triple pipe, ⟨⦀⟩, may have been used by other authors for the same thing.) They then went largely unnoticed until ca. 2005.
(For Damin, the retroflex nasal click, which may or may not be similar to the clicks of Central !Kung, was transcribed with the Kirschenbaum convention, n.!.)
Miller (2009) notes that the Grootfontein retroflex clicks have a lateral release, and alternatively transcribes them ⟨ǃǁ⟩. Whereas the alveolar and alveolar lateral clicks are apical, these are laminal and postalveolar; where the others are powered by tongue-root retraction, these are powered by lowering the center of the tongue (Miller 2009). They obey the back-vowel constraint common among retroflex consonants. (Neither characteristic is likely to have applied to Damin.)
Basic retroflex clicks are:
|Trans. I||Trans. II||Description|
|⟨‼⟩||tenuis retroflex click|
|⟨‼ʰ⟩||aspirated retroflex click|
|⟨‼̬⟩||⟨ᶢ‼⟩||voiced retroflex click|
|⟨‼̃⟩||⟨ᵑ‼⟩||retroflex nasal click|
|⟨‼̥̃ʰ⟩||⟨ᵑ̊‼ʰ⟩||aspirated retroflex nasal click|
|⟨‼̃ˀ⟩||⟨ᵑ‼ˀ⟩||glottalized retroflex nasal click|
Features of postalveolar clicks:
- The basic articulation may be voiced, nasal, aspirated, glottalized, etc.
- 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.
- Clicks may be oral or nasal, which means that the airflow is either restricted to the mouth, or passes through the nose as well.
- It is a lateral consonant, which means it is produced by directing the airstream over the sides of the tongue, rather than down the middle.
- The airstream mechanism is lingual ingressive (aka velaric ingressive), which means a pocket of air trapped between two closures is rarefied by a "sucking" action of the tongue, rather than being moved by the glottis or the lungs/diaphragm. The release of the forward closure produces the 'click' sound. Voiced and nasal clicks have a simultaneous pulmonic egressive airstream.
As with other click articulations, retroflex clicks may be produced with various manners. An example is the voiced retroflex click in the Grootfontein !Kung (Central Juu) word for 'water', /ǃ̬˞ ˡú/ (g‼ú).
Damin is the only other language known to have had such a sound, though only the nasal click occurred.
- Scott, Miller, Namaseb, Sands, & Shah, 2010. Retroflex clicks in two dialects of !Xung. University of Botswana.
- The standard IPA diacritic for lateral release, ⟨ǃˡ⟩, would presumably also work.
See also 
- The fricated alveolar click of Ekoka !Kung, which was once thought to be retroflex
- Alveolar clicks
- Bilabial clicks
- Dental clicks
- Lateral clicks
- Palatal clicks