In phonetics, the labiodental flap is a speech sound found primarily in languages of Central Africa, such as Kera and Mangbetu. It has also been reported in the Austronesian language Sika. It is one of the few non-rhotic flaps. The sound begins with the lower lip placed behind the upper teeth. The lower lip is then flipped outward, striking the upper teeth in passing.
The symbol in the International Phonetic Alphabet that represents this sound is ⟨?⟩, which resembles Cyrillic izhitsa, ⟨?⟩, but is composed of a V and the hook of the flap ⟨?⟩. In 2005, the International Phonetic Association, responding to Dr. Kenneth S. Olson's request for its adoption, voted to include a symbol for this sound, and selected a v with a right hook. This symbol is a combination of ⟨v⟩ + ⟨?⟩ (the letters for the voiced labiodental fricative and the alveolar flap). As of version 5.1.0, the Unicode character set encodes this character at U+2C71 (?). In earlier literature, it is often transcribed by a v modified by the extra-short diacritic, ⟨v?⟩, following a 1989 recommendation of the International Phonetic Association. Another historic symbol for this sound was v with curl ⟨?⟩, which had been employed in articles from the School of Oriental and African Studies, by Joseph Greenberg, and others.
Features of the labiodental tap:
The labiodental flap is found primarily in Central Africa, in as many as a few hundred languages found in the Chadic family (Margi, Tera), Ubangian (Ngbaka, Ma'bo, Sera), Mbum (eg Kare), Central Sudanic (Mangbetu, Kresh), and Bantoid (Ngwe, some Shona dialects). It is extremely rare outside Africa, though it has been reported from Sika in Flores.
|Bana||[?evin]||'fishhook'||Mainly restricted to ideophones, and between high central vowels. Contrasts with /v/.|
|Kera||[vehti]||'push your head out of a hole or out of water'||Since most of the lexical items are ideophones, it is not definitively the case that the labial flap has been fully incorporated into the phonological system of Kera.|
|Mono||vwa||[?a]||'send'||Contrasts with /v/ and /w/. In free variation with bilabial flap|
|Sika||[voti]||'I stand a pole in the ground'||Contrasts with /v/ and /?/. May also be realized as [b?]|
The bilabial flap [?] is a variant of the labiodental flap in several languages, including Mono. This sound involves striking the upper lip rather than the upper teeth. The two sounds are not known to contrast in any language; the term labial flap can be used as a broader description encompassing both sounds.
In Sika, the flap is heard in careful pronunciation, but it may also be realized as a voiced labiodental stop, [b?], or an affricate. It contrasts with both a bilabial and a labiodental fricative:
|[voti]||"I stand a pole in the ground"|
|[phehte]||"We (inclusive) buy"|