Labial-coronal consonant

Labial-alveolar

Labial-alveolar consonants are doubly articulated consonants that are co-articulated at the lips and the front part of the tongue against the alveolar ridge or the alveolar ridge and the teeth. They are only well-attested in Yelî Dnye.

Several labial-alveolar consonants are attested in Yelî Dnye, where the alveolar contact is more precisely denti-alveolar: a voiceless plosive /t̪͡p/, a nasal /n̪͡m/, and prenasalized /ⁿd̪͡b/ (also analyzed as /ⁿt̪͡p/ but phonetically voiced), of which /t̪͡pʲ/ and /ⁿd̪͡bʲ/ may also occur palatalized.

Labial-postalveolar

Labial-postalveolar consonants are doubly articulated consonants that are co-articulated at the lips and the postalveolar plate. They are only attested in some dialects of Setswana.

Several labial-postalveolar consonants are attested in Setswana, including a voiceless fricative [ɸ͡ʃ] and voiceless affricate [p͡ʃ], aspirated affricate [p͡ʃʰ], and voiced affricate [b͡ʒ]. However, there is debate as to whether they are truly doubly articulated, and may in fact be more similar to labialized postalveolars, in which case [ɸ͡ʃ] would be reanalyzed as [ʃᶲ].

Labial-retroflex

Labial-retroflex consonants are doubly articulated consonants that are co-articulated at the lips and with the front part or underside of the tongue against the palate. They are only well-attested in Yelî Dnye.

Several labial-retroflex consonants are attested in Yelî Dnye. These include a voiceless plosive /ʈ͡p/, an allophonic voiced plosive /ɖ͡b/, a nasal /ɳ͡m/, prenasalized /ɳ͡mɖ͡b/ (also analyzed as /ɳ͡mʈ͡p/ but phonetically voiced), and postnasalized /ʈ͡pɳ͡m/, all or most of which may also occur palatalized: /ʈ͡pʲ/, /ɳ͡mʲ/, /ʈ͡pɳ͡mʲ/ and possibly /ɳ͡mɖ͡bʲ/ and /ɖ͡bʲ/. [ʈ͡pɳ͡mɖ͡b͡ɭ] also appears in it. Yelî Dnye is unique in having this series of consonants.

In some Ghanaian languages such as Dagbani, and Nzema, there are palatalized allophones of labial-velars. These are sometimes mistakenly referred to as labial-alveolars, though they actually have a post-alveolar or palatal articulation instead of a true alveolar one.

Something similar is found with the labialized alveolar stops in several Northwest and Northeast Caucasian languages such as Abkhaz and Lak. Although the double stop articulation may be more common, they are generally considered to be essentially labialized alveolars because the labial contact is light, and moreover the contact is between the inner surfaces of the lips, which are protruded as they are for [w]. This is quite different from the normal contact for [p] in these languages. The labial contact may also be realized as a trill. Compare the following minimal sets in Ubykh:

Some speakers of !Xóõ have a labial-dental allophone, [ʘ͡ǀ] (or [ɋ͡ʇ]), of the bilabial click /ʘ/ in some cases (Traill 1985: 103-104).

Discounting clicks otherwise as having a velar/lingual airstream mechanism rather than a double articulation, nearly all other doubly articulated consonants in the world are labial-velars. The labial-alveolars reported from some Chadic languages have upon investigation turned out to be /tp/, /db/, /nm/ and /dɓ/ sequences, not single consonants. (See Margi language.)