Kenneth S. Olson


The Labiodental flap

Articulation of the word [àⱱ̟étòrò] 'stick used in an animal trap (Mono, DRC). From Olson and Hajek (2004).

NOTE: Some special characters on this page require either the Charis SIL font or the Doulos SIL font.

labiodental flap

Kenneth Olson conducts research (along with John Hajek of the University of Melbourne) on the labiodental flap [ⱱ], a speech sound found mostly in the north central part of Africa. The research includes documenting its geographic and genetic distribution, studying its articulatory and acoustic features, and examining its phonological status. A labiodental articulation is most common cross-linguistically, but a bilabial flap is also attested, e.g. Mangbetu (Demolin & Teston 1996), Mono (Olson 2005), and Mambay (Anonby 2007). The term labial flap can be used to encompass both the labiodental and bilabial articulations (Catford 1977: 145).¹

In May 2005 the Council of the International Phonetic Association voted to adopt a symbol for the labiodental flap. The symbol they chose is the right-hook v [ⱱ].

The right-hook v symbol was added to Unicode in version 5.1 at code point U+2C71. Fonts that includes the symbol at this code point include Doulos SIL, Charis SIL, Gentium Plus, Code2000, DejaVu Sans, LaserIPA in Unicode,² and Geneva Regular (found on Macs). The Unicode name for the symbol is latin small letter v with right hook. Note that this is different from the latin small letter v with hook symbol [ʋ] at code point U+028B. The right-hook v character is similar to the Cyrillic small letter izhitsa [ѵ] (U+0475).

The bilabial flap can be represented by adding the ‘advanced’ diacritic to the right-hook v base symbol [ⱱ̟]. This was suggested by Olson & Hajek (1999: 112) and first implemented for language data by Anonby (2006).

IPA Braille, developed by Robert Englebretson in conjunction with the International Council on English Braille, contains the labiodental flap (dots 235–1236). See Englebretson (2009: 83).

The first known mention of the labiodental flap in the literature was in 1907 by the French Catholic missionary Pierre Cotel, who worked in what is present-day Central African Republic. In his small grammar and dictionary of the Togbo dialect of Banda, Cotel describes a sound that “se prononce en faisant rentrer la lèvre inférieure sous les incisives de la mâchoire supérieure” (p. x).

The first known use of the right-hook v symbol to represent the labiodental flap sound was in a 1988 article by Didier Demolin in the Belgian Journal of Linguistics. Demolin’s tentative description of the articulation of the sound in this article was refined in his later work.

Labiodental flap data

The online article, A crosslinguistic lexicon of the labial flap, by Olson and Hajek, contains data on the labiodental flap from 75 languages, including 38 audio recordings (MP3 format) and one video recording (QuickTime MOV format) from the Mono language. The recordings are in section 5.1.6 of the paper.

Since the publication of this article, Dr. Olson has compiled the following additional data on the labiodental flap.

Blench 2006

Blench, Roger. 2006. Archaeology, language, and the African past. (The African archaeology series 10). Lanham, MD: AltaMira Press.

From p. 52:

Diffused features can be quite evident when they are distinctive lexical items, for example, recent loanwords. But there are clearly many ancient diffused linguistic features in African languages that can only be identified in the context of a fairly detailed knowledge of the affiliation of languages in a circumscribed geographical area. A good example of this is the labio-dental flap, an unusual sound found in a wide swathe of languages across Central Africa. This sound was first identified as widespread by Thomas (1971) and mapped in Africa-wide detail by Greenberg (1983) and more fully in Olson and Hajek (2003). It is found nowhere else in the world except for a possible case in Sika (an Austronesian language), and in Africa it is spread evenly across three of the four main phyla: Afroasiatic, Nilo-Saharan, and Niger-Congo. Despite being very distinctive, its source region and original genetic affiliation remains unknown. It is a typical feature that has no implication for genetic affiliation.

Catford 1977

Catford, J. C. 1977. Fundamental problems in phonetics. Edinburgh: Edinburgh University Press. [1982 edition: Bloomington, IN: Indiana University Press.]

The labiodental flap is mentioned on p. 129:

Another variety of this type of ‘transient flap’, in which a moving articulator momentarily strikes a static articulator in passing, is the ‘labio-dental flap’ of the West African language, Margi. In this sound, which appears to be really a sequence of labio-dental stop and flap, the lower lip starts somewhat bent back behind the upper teeth. It then shoots forward, striking against the edges of the upper teeth in passing, to end up in the normal, rest position. For a full description see Ladefoged (1964, p. 18).

Chomsky & Halle 1968

Chomsky, Noam & Morris Halle. 1968. The sound pattern of English. (Studies in Language.) New York: Harper & Row.

The labiodental flap is mentioned on p. 321:

We have seen that each closure in the vocal tract may be released instantaneously or with a delay. There are, however, important restrictions on the release features. Only sounds produced with closure can have different types of release. Ladefoged (1964) describes a labiodental flap (in Margi) which consists in effect of a labiodental fricative terminating in an instantaneous release. This sound, however, occurs only in “ideophones,” e.g., in utterances such as bə́vbú, “describing sudden appearance and flight,” hávbáwù, “describing escape of an animal,” kávbáhù, “describing intruding into a place” (Hoffmann, 1963, pp. 25f.), which occupy a clearly marginal position in the phonological system.

NB: It’s unclear why Chomsky & Halle consider the sound a fricative. Ladefoged (1964) does not (to our knowledge) suggest that the sound is a fricative.

Clark & Yallop 1995

Clark, John & Colin Yallop. 1995. An introduction to phonetics and phonology. Second edition. (Blackwell Textbooks in Linguistics 9). Oxford: Blackwell.

This textbook mentions the labiodental flap on p. 48:

Ladefoged (1982, p. 155) also reports a labiodental flap (from Margi, a language of Nigeria) in which the lower lip is drawn in and then allowed to flap against the upper teeth as it returns forward.

Clements 1999

Footnote [10] on p. 24 states:

Mbum, a Niger-Congo language spoken in Cameroon, is cited by Maddieson (1992) as having a voiced labiodental plosive. But this sound, represented as “V” by his source (Hagège 1971), is described there as a “labiodental occlusive,” and in later work by the same author as a “labiodental flap” (Hagège 1975). Labiodental flaps occur with some frequency in central African languages (Greenberg 1981, Cloarec-Heiss 1998). However these sounds are to be characterized phonologically, they pose no problem for the present analysis, since Mbum has no contrasting labiodental affricate."

Ladefoged 1971

Ladefoged, Peter. 1971. Preliminaries to linguistic phonetics. Chicago: University of Chicago Press.

The labiodental flap is discussed on pp. 52–53:

Margi has a kind of labiodental flap, photographs of which have been published elsewhere (Ladefoged 1964a). The articulation is fairly complex and does not fit into any of the categories defined above. The lower lip is first pulled backward against the upper teeth, contact being maintained at the same time with the upper lip. Then there is a downward movement so that the lower lip comes away from the upper lip, slips off the upper teeth, and (because of the backward pull which is being exerted) moves in behind the upper front teeth. As it is brought back from this position to its normal position, it flaps against the upper teeth. A similar sound occurs in Shona; good photographs have been published by Doke (1931). My Shona informants pronounced this sound without the first stage, the tensing of the lower lip against the upper teeth found in Margi; in Shona the lower lip is simply drawn back behind the upper teeth, and then flapped forward with a much looser action. Some words contain two of these flaps in succession. Similar sounds have been reported in other African languages (Westermann and Ward 1933; Tucker 1940).
Table 32: Contrasts involving labiodental flaps in Shona (suggested by George Fortune). This articulation is here indicated by *
ko*ó ideophone indicating blackness
wó*o ideophone indicating movement

Ladefoged 2001

Ladefoged, Peter. 2001 [1975]. A course in phonetics. Fourth edition. Fort Worth, TX: Harcourt College Publishers.

This textbook mentions the labiodental flap on p. 155:

I have also heard a labiodental flap—in Margi, of Northern Nigeria—in which the lower lip is drawn back inside the upper teeth and then allowed to strike against them in passing back to its normal position. There is no IPA symbol for this sound. I have included this rare sound so as to demonstrate how to symbolize a sound for which there is no IPA symbol. In all such cases, it is possible to use an asterisk and define it…

Nida 1950

Nida, Eugene A. 1950. Learning a foreign language: A handbook for missionaries. New York: Committee on Missionary Personnel of the Foreign Missions Conference of North America.

This handbook mentions the bilabial flap on p. 101:

A labial flap occurs in Ngbaka. In the production of this sound the lower lip is first drawn in behind the upper teeth and upper lip. It is then drawn out rapidly past the upper lip against which it flaps. The sound occurs in the word kàkáb̌à “crow.”

NB: The language data are underlined (not italicized) in the original.

Nida notes that the Ngbaka have the practice of removing their two front teeth. Pike (1947:37) notes this practice for Mbandja. Contrary to Mbandja, however, Nida suggests that this practice does not affect the pronunciation of Ngbakas (pp. 87–88):

Certain tribes place disks in their lips and file their teeth or knock out certain teeth for the sake of adornment. One would think that such disfigurements would modify the speech appreciably, but that does not seem to be the case. The Ngbakas who have their two front upper teeth knocked out (the normal practice in the tribe) do not speak appreciably different from those who do not have such teeth removed.

Pike 1943

Pike, Kenneth L. 1943. Phonetics: A critical analysis of phonetic theory and a technic for the practical description of sounds. Ann Arbor, MI: University of Michigan Press.

Pike mentions a “labioalveolar flap” on p. 125:

One hears but rarely of any flaps except those with the tongue tip articulating against the alveolar arch, but others with the same type of quick percussive effect are possible. A labioalveolar flap in which the lower lip taps against the upper gum is one of these.

Pike 1947

Pike, Kenneth L. 1947. Phonemics: A technique for reducing languages to writing. Ann Arbor, MI: University of Michigan Press.

This textbook mentions a “labio-alveolar flap” on p. 37. Evelyn Pike (p.c.) confirms that the sound in question is a labiodental flap.

Exercise 3. Make a labio-alveolar flap¹ by curling the lower lip inward and backward and giving it a single flap outward so that in its outward passage it produces a kind of “pop” as it brushes against the alveolar arch or the teeth.

Pike describes a bilabial flap in a footnote on the same page:

¹When members of the Mbanza tribe of the northwestern corner of Belgian Congo have followed the custom of removing the four upper teeth they form their regular labiodental flap against the upper lip instead of against the upper teeth. Data from R. B. Anderson.

NB: Nida (1950:87–88) has a different assessment from Pike of the effect of tooth extraction in speech production.

Trask 1996

Trask, R. L. 1996. A dictionary of phonetics and phonology. London: Routledge.

Trask mentions the labiodental flap in the entry for the word ‘flap’ on p. 145:

…several African languages have a labiodental flap for which Ladefoged has proposed the symbol [vb].

Westermann & Ward 1933

Westermann, Diedrich & Ida C. Ward. 1933. Practical phonetics for students of African languages. London: Oxford University Press (for the International African Institute). [1990 edition published by Paul Kegan International, London.]

Westermann & Ward mention a labiodental flap on p. 76:

Another flapped sound was found by Dr. Tucker in Kreish (Gbaya). ‘This is rather like a v made by flapping the lower lip against the upper teeth. It is written vv (for want of a suitable letter) and is rather rare.’ [vb has been suggested to represent this sound.] Doke uses the symbol  in his “Shona phonetics”.
gevve ‘arrow’ gevvumu ‘to shoot with a bow’


¹ “In practice, however, it is very often possible to use abbreviated terms: thus bilabial to mean labio-labial: or even labial to mean this and also labio-dental” (Catford 1977: 145).

² See


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Copyright © 2013 Kenneth S. Olson.