The voiced retroflex approximant is a type of consonant used in some languages. The symbol in the International Phonetic Alphabet that represents this sound is ⟨ɻ⟩, and the equivalent X-SAMPA symbol is r\`. The IPA symbol is a turned lowercase letter r with a rightward hook protruding from the lower right of the letter.
Its place of articulation is retroflex, which prototypically means it is articulated subapical (with the tip of the tongue curled up), but more generally, it means that it is postalveolar without being palatalized. That is, besides the prototypical subapical articulation, the tongue contact can be apical (pointed) or laminal (flat).
Its phonation is voiced, which means the vocal cords vibrate during the articulation.
It is an oral consonant, which means air is allowed to escape through the mouth only.
It is a central consonant, which means it is produced by directing the airstream along the center of the tongue, rather than to the sides.
Might be rarely used to transliterate Tamil or Malayalam or to write proper nouns of Tamil or Malayalam. Usage is practically non existent and almost always merged with [ɭ], in both written and spoken forms, by modern speakers.
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Sadowsky, Scott; Painequeo, Héctor; Salamanca, Gastón; Avelino, Heriberto (2013), "Mapudungun", Journal of the International Phonetic Association, 43 (1): 87–96, doi:10.1017/S0025100312000369
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