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 can be apical (pointed) or, in some fricatives, 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.
Apical.[1] As an initial in free variation between fricative and approximant, but never has friction as strong as a true fricative (Chinese "fully muddy"/全浊-class) to trigger a (free or conditional) devoicing or postvoicing into /ʐ̥ʱ/, nor weak enough to become an apical vowel. As a rime it's an apical vowel that is frequently coarticulated with a close near-back unrounded vowel /ɨ̟/ (thus phonetically [ɻ̺͢ɨ̟͡ɻ̺̞̍˥˩ku̯ɑ͢ŋ˥], but this phonetic representation should be avoided as the tie-bar for coarticulation may be misunderstood as a sliding into an erhuarhotic vowel, a phonemically distinct syllable in Chinese), but it can be prolonged indefinitely and never truly developed into an /ɨ̟/. Both the consonant and the vowel may gain some friction especially when prolonged to force a more "distinct/clear" effect in teaching or when swearing, and thus it may be inaccurately transcribed as fricative [ʐ] both as initial and as rime (when precision is necessary, a true fricative in Wu Chinese may be transcribed as [ʐ̥ʱ], as that's how it's pronounced in the first syllable). See Standard Chinese phonology.
The character 日 (sun), when pronounced with an overall strengthened friction (on both z and ɿ), may likely be understood as a profanity, thus pronouncing as an approximant is important; but the two do not form a minimal pair, because the profanity can also be pronounced with little friction (though in some other dialects they further evolved to form a minimal pair).
Árnason, Kristján (2011), The Phonology of Icelandic and Faroese, Oxford University Press, ISBN978-0-19-922931-4
Keane, Elinor (2004), "Tamil", Journal of the International Phonetic Association, 34 (1): 111–116, doi:10.1017/S0025100304001549
Sadowsky, Scott; Painequeo, Héctor; Salamanca, Gastón; Avelino, Heriberto (2013), "Mapudungun", Journal of the International Phonetic Association, 43 (1): 87–96, doi:10.1017/S0025100312000369
Trudgill, Peter (1989), "The Sociophonetics of /l/ in the Greek of Sphakiá", Journal of the International Phonetic Association, 15 (2): 18–22, doi:10.1017/S0025100300002942, S2CID143943154
