Retroflex flap

The retroflex flap is a type of consonantal sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is ɽ, and the equivalent X-SAMPA symbol is r`.

Toda has a retroflex trill, which is transcribed with the same IPA symbol.

[edit] Features

Features of the retroflex flap:

Its manner of articulation is flap, which means it is produced with a single contraction of the muscles so that one articulator is thrown against another.
Its place of articulation is retroflex, which prototypically means it is articulated with the tip of the tongue curled up, but more generally means that it is postalveolar without being palatalized.
Its phonation type is voiced, which means the vocal cords are vibrating during the articulation.
It is an oral consonant, which means air is allowed to escape through the mouth.
It is a central consonant, which means it is produced by allowing the airstream to flow over the middle of the tongue, rather than the sides.
The airstream mechanism is pulmonic egressive, which means it is articulated by pushing air out of the lungs and through the vocal tract, rather than from the glottis or the mouth.

Hausa: bara [bəɽa] "servant"
American English: As an allophone of /t/ and /d/ after /r/ and before a vowel: e.g. 'hurting' [hɝɽɪŋ], but only for speakers with a retroflex approximant. Also, a nasalized retroflex flap can occur as an allophone of /n/ in words like 'burning' [bɝɽ̃ɪŋ].
certain dialects of Swedish and eastern and central dialects of Norwegian: blad [bɽɑːd] "leaf; blade; page"
Hindi and Urdu: [bəɽɑː] "big". It also has an aspirated counterpart: [ɽʰ], e.g., [pəɽʰnɑː] "to study/read".

Consonants (List, table)