Crosslinguistic insights on the labial flap KENNETH S. OLSON and JOHN HAJEK Linguistic Typology 7 (2003), 157–186 1430–0532/2003/007-0157 c Walter de Gruyter Abstract This paper is a crosslinguistic study of the labial flap – an areal feature con- centrated in north central Africa, but also attested in southeastern Africa and Indonesia. It is found in three of the four major African language families, but is likely not traceable to the proto-language of these families. Its most common articulation is a voiced labiodental flap with egressive lung air. It is fully incor- porated into the phonological system of at least thirteen languages, and there is good evidence for this in an additional nine languages. Consequently, theo- ries of phonological features or phonetic parameters must take it into account. It is most widely attested in the Adamawa-Ubangi branch of Niger-Congo, and this may be its ultimate source as well, supporting Greenberg’s (1959, 1983) hypothesis concerning the source of some African areal features. Keywords: Adamawa-Ubangi, Africa, areal diffusion, articulatory phonetics, ideophone, labial flap, phoneme system 1. Introduction The labial flap is a speech sound most commonly found in the north central savanna region of Africa. It is attested in at least seventy languages in Africa and one in Indonesia. In this crosslinguistic study, we discuss its areal and genetic distributions, and we draw generalizations regarding its articulation and phonological status. These observations have implications for researching the historical development of the sound. Our data come from an extensive survey of the literature as well as previously unpublished data from both our own field work and that of other researchers. The labial flap is produced by retracting the lower lip into the mouth well behind the upper teeth and then bringing it forward rapidly, striking the upper lip or teeth in passing. Photographs showing the articulation of the sound in