Voiced labiodental nasal

The voiced labiodental nasal is a type of consonantal sound. The symbol in the International Phonetic Alphabet that represents this sound is ⟨ɱ⟩. The IPA symbol is a lowercase letter m with a leftward hook protruding from the lower right of the letter. Occasionally it is instead transcribed as an with a dental diacritic: ⟨m̪⟩ (for example in extIPA, where the two transcriptions are presented as variants).

The labiodental pronunciation of is very similar to that of the bilabial nasal, but instead of the lips touching each other, the lower lip touches the upper teeth. The position of the lips and teeth is generally the same as for the production of the labiodental fricatives and, though air escapes between the lip and the teeth in the case of the fricatives.

Although commonly appearing in languages, it is overwhelmingly an allophone restricted to a position before the labiodental consonants and. A phonemic has only been reported for the Kukuya language, which contrasts it with  and is "accompanied by strong protrusion of both lips". It is before  and  before  and, perhaps because labialization is constrained by the spread front vowels; it does not occur before the back (rounded) vowels  and.

It is doubted by some scholars that true closure can be made by a labiodental gesture because of gaps between the incisors, which for many speakers would allow air to flow during the occlusion. This is particularly pertinent considering that one of the Kukuya words with this consonant,, means a 'gap between filed incisors,' a practice of the local people. The might therefore be better characterized as a labiodental nasal approximant than as a nasal occlusive.

Nonetheless, is extremely common around the world phonetically, as it is the universal allophone of  and a very common allophone of  before the labiodental fricatives  and, as for example in English comfort and circumvent, and, for many people, infinitive and invent. In the Angami language, occurs as an allophone of  before. In Drubea, is reported as an allophone of  before nasal vowels.

A proposal to retire the letter ⟨ɱ⟩ was made in the run-up to the Kiel Convention of 1989, with the labiodental nasal to be transcribed solely by ⟨m̪⟩, but the proposal was defeated in committee.

Features


Features of the voiced labiodental nasal:

Occurrence
Phonemic is extremely rare. As an allophone of nasal consonants before or, however,  is very common.