|Nasal labio-velar approximant
The nasal labio-velar approximant is a type of consonantal sound used in some oral languages. The symbol in the International Phonetic Alphabet that represents this sound is ⟨w̃⟩, that is, a w with a tilde. The equivalent X-SAMPA symbol is w~.
The nasal approximants [ȷ̃] and [w̃] may also be called nasal glides. In some languages like Portuguese, they form a second element of nasal diphthongs.
Features of the nasal labio-velar approximant:
- Its manner of articulation is approximant, which means it is produced by narrowing the vocal tract at the place of articulation, but not enough to produce a turbulent airstream.
- Its place of articulation is labialized velar, which means it is articulated with the back part of the tongue raised toward the soft palate (the velum) while rounding the lips.
- Its phonation is voiced, which means the vocal cords vibrate during the articulation.
- It is a nasal consonant, which means air is allowed to escape through the nose, either exclusively (nasal stops) or in addition to through the mouth.
- It is a central consonant, which means it is produced by directing the airstream along the center of the tongue, rather than to the sides.
- The airstream mechanism is pulmonic, which means it is articulated by pushing air solely with the lungs and diaphragm, as in most sounds.
See also 
- Barbosa, Plínio A.; Albano, Eleonora C. (2004), "Brazilian Portuguese", Journal of the International Phonetic Association 34 (2): 227–232, doi:10.1017/S0025100304001756