Labial–coronal consonant

A labial–coronal consonant is a consonant produced with two simultaneous articulators: with the lips ('labial'; a [p], [b], or [m] sound), and with the tongue (at the teeth or gums, a 'dental' or 'alveolar' [t], [d] or [n] sound, or further back, a 'post-alveolar' or 'retroflex' [ʈ], [ɖ] or [ɳ] sound).

Several languages have been claimed to have such sounds, such as Margi and Bura in Nigeria. However, most researchers interpret them as having sequences of labial and coronal consonants, a rather common occurrence in Africa. The Yélî Dnye language^[1][2] of Rossel Island, Papua New Guinea, appears to be unique in having distinct laminal labial–alveolar (i.e. labial–denti-alveolar) and labial–retroflex (i.e. apical to sub-apical labial–postalveolar) places of articulation, as illustrated below.

Stops in Yelî Dnye	Bilabial		Alveolar		Retroflex		Velar
Stop	paa	side	t̪aa	knife	ʈoo	tongue	kaa	spear
Prenasalized stop	mbee	carry	n̪d̪e	food	ɳɖe	firewood	ŋɡaa	tree
Nasal	maa	road	n̪ii	juice	ɳaa	feast	ŋa	lease

Stops in Yelî Dnye	Labial–alveolar		Labial–retroflex		Labial–velar
Stop	t̪͡pənə	lung	ʈ͡pənə	horn	k͡pene	coconut bag
Prenasalized stop	n͡md̪͡boo	pulp	ɳ͡mɖ͡boo	many	ŋ͡mɡ͡bo	fog
Nasal	n̪͡mo	bird	ɳ͡mo	we	ŋ͡mo	breast

Labial–coronal allophones

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:

da	now	dʷa ~ d͡ba ~ d͡ʙa	awl	ba	if
ta	pregnant	tʷa ~ t͡pa ~ t͡ʙ̥a	cherry	pa	to weave
tʼə	ram	tʷʼə ~ t͡pʼə ~ t͡ʙ̥ʼə	to take out

Some speakers of !Xóõ have a labial–dental allophone, [ʘ͡ǀ] (or [ʘ͡ʇ]), 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.)