Labial–velar consonant

Labial–velar consonants are doubly articulated at the velum and the lips, such as [k͡p]. They are sometimes called "labiovelar consonants", a term that can also refer to labialized velars, such as the stop consonant [kʷ] and the approximant [w].

Labial-velars are often written as digraphs. In the Kâte language, however, /k͡p/ is written Q q, and /ɡ͡b/ as Ɋ ɋ.

Globally, these types of consonants are quite rare, only existing in two regions: West and Central Africa on the one hand, Eastern New Guinea^[1] and northern Vanuatu^[2] on the other. There are 2 other isolated cases, allophonically in Vietnamese and in the Adu dialect of Nuosu (Yi).

Truly doubly articulated labial-velars include the stops [k͡p, ɡ͡b], the nasal [ŋ͡m], and the implosive [ɠ͜ɓ]. To pronounce them, one must attempt to say the velar consonants but then close their lips for the bilabial component, and then release the lips. While 90% of the occlusion overlaps, the onset of the velar occurs slightly before that of the labial, and the release of the labial occurs slightly after that of the velar so the preceding vowel sounds as if it were followed by a velar, and the following vowel sounds as if it were preceded by a labial. The order of the letters in ⟨k͡p⟩ and ⟨ɡ͡b⟩ is therefore not arbitrary but motivated by the phonetic details of the sounds.

Phonemic labial–velars occur in the majority of languages in West and Central Africa (for example in the name of Laurent Gbagbo, former president of Ivory Coast; they are found in many Niger–Congo languages as well as in the Ubangian, Chadic and Central Sudanic families), and are relatively common in the eastern end of New Guinea. The rare implosive is only found in Lese, a Nilo-Saharan language of the Democratic Republic of the Congo.^[3][4] In Southeast Asia, they occur in the Adu dialect of Nuosu (Yi), which aside from its isolated location, is unusual in having a relatively large inventory of labial-velar consonants, including the rare aspirated version: /k͡pʰ, k͡p, ɡ͡b, ᵑɡ͡b, ŋ͡m/.^[5]

Labial–velar stops can also occur as an ejective [k͡pʼ] (unattested) and a voiceless implosive [ƙ͜ƥ]. Floyd (1981) and Clark (1990) report that voiced and voiceless implosives /ɠ͡ɓ, ƙ͜ƥ/ occur in Central Igbo. As stated above, the voiced implosive has been confirmed in Lese.

The Yele language of Rossel Island, Papua New Guinea, has both labial–velars and labial–alveolar consonants. Labial–velar stops and nasals also occur in Vietnamese but only word-finally.

These sounds are clearly single consonants rather than consonant clusters. For example, Eggon contrasts /bɡ/, /ɡb/, and /ɡ͡b/. The following possibilities are possible if tone is ignored:

Allophonic labial-velars are known from Vietnamese, where they are variants of the plain velar consonants /k/ and /ŋ/.

Some languages, especially in Papua New Guinea and in Vanuatu, combine the labial–velar consonants with a labial–velar approximant release: [k͡pʷ], [ŋ͡mʷ]. The extinct language Volow had a prenasalised labial-velar stop with labialization [ᵑ͡ᵐɡ͡bʷ].^[7][8]

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Bilabial clicks are stops that involve closure at both the lips and the soft palate. Treatments often analyze the dorsal articulation as part of the airstream mechanism, and so consider such stops to be labial. However, there may be a distinction between the velar labial clicks [k͡ʘ ɡ͡ʘ ŋ͡ʘ] and the uvular labial clicks [q͡ʘ ɢ͡ʘ ɴ͡ʘ], which is not captured if they are described as simply labial.

• Place of articulation
• List of phonetics topics

• Ladefoged, Peter; Maddieson, Ian (1996). The Sounds of the World's Languages. Oxford: Blackwell. ISBN 0-631-19815-6.