Voiceless alveolar tap and flap

The voiceless alveolar tap or flap is rare as a phoneme. The symbol in the International Phonetic Alphabet that represents this sound is ⟨ɾ̥⟩, a combination of the letter for the voiced alveolar tap/flap and a diacritic indicating voicelessness. The equivalent X-SAMPA symbol is 4_0.

The voiceless alveolar tapped fricative reported from some languages is actually a very brief voiceless alveolar non-sibilant fricative.

Features

Features of the voiceless alveolar tap or flap:

Its manner of articulation is tap or flap, which means it is produced with a single contraction of the muscles so that the tongue makes very brief contact.
Its place of articulation is dental or alveolar, which means it is articulated behind upper front teeth or at the alveolar ridge. It is most often apical, which means that it is pronounced with the tip of the tongue.
Its phonation is voiceless, which means it is produced without vibrations of the vocal cords. In some languages the vocal cords are actively separated, so it is always voiceless; in others the cords are lax, so that it may take on the voicing of adjacent sounds.
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.
Its airstream mechanism is pulmonic, which means it is articulated by pushing air solely with the intercostal muscles and abdominal muscles, as in most sounds.

Language		Word	IPA	Meaning	Notes
Bengali^[1]		আবার	[ˈäbäɾ̥]	'again'	Possible allophone of /ɹ/ in the syllable coda.^[1] See Bengali phonology
English		throw	[θɾ̪̊oʊ]	'throw'	Allophone of /ɹ/ after /θ/.
Greek	Cypriot	αρφός	[ɐɾ̥ˈfo̞s]	'brother'	Allophone of /ɾ/ before voiceless consonants. May be a voiceless alveolar trill instead
Icelandic		hrafn	[ˈɾ̥apn̪̊]	'raven'	Realization of /r̥/ for some speakers. Also illustrates /n̥/. See Icelandic phonology
Portuguese	European^[2]	assar	[əˈsäɾ̥]	'to bake'	Apparent allophone of /ɾ/; distribution unclear, but common in the coda in Jesus (2001)'s corpus. See Portuguese phonology

Jesus, Luis Miguel Teixeira (2001), Acoustic Phonetics of European Portuguese Fricative Consonant (Ph.D.), University of Southampton
Khan, Sameer ud Dowla (2010), "Bengali (Bangladeshi Standard)" (PDF), Journal of the International Phonetic Association, 40 (2): 221–225, doi:10.1017/S0025100310000071

v t e The letter R
General	Rhotic consonants (R-like sounds) Perception of English /r/ and /l/ by Japanese speakers Pronunciation of English /r/ Rhoticity in English R-colored vowel Rhotacism Guttural R Linking and intrusive R
Pronunciations	Voiceless alveolar trill [r̥] Voiced alveolar trill [r] Voiced alveolar or postalveolar approximant [ɹ] Voiceless alveolar tap [ɾ̥] Voiced alveolar tap [ɾ] Voiced alveolar lateral flap [ɺ] Voiced retroflex approximant [ɻ] Voiced retroflex flap [ɽ] Voiced retroflex trill [ɽr] Voiced velar approximant [ɰ] Voiced velar bunched approximant [ɹ̈] Voiceless velar fricative [x] Voiced velar fricative [ɣ] Voiceless uvular trill [ʀ̥] Voiced uvular trill [ʀ] Voiceless uvular fricative [χ] Voiced uvular fricative [ʁ] Voiced pharyngeal fricative [ʕ] Voiceless glottal fricative [h] Voiced glottal fricative [ɦ]
Variations	Ꝛꝛ (R rotunda) Ꞃꞃ (Insular) Ɽɽ (R with tail) Ɍɍ (R with stroke) Ʀʀ Ȑȑ Ŕŕ Ŗŗ Řř Ȓȓ R̃r̃ Ṙṙ Ṛṛ R̄r̄ Ṝṝ Ṟṟ Rd Rh Rl Rm Rn Rp Rr Rs Rt Rw Rz Rnd ᚱ (Raidô) ℝ (Real number) ® (Registered trademark symbol) Ⓡ (Enclosed R) ℞ (Medical prescription)