A nasal consonant is one in which the air escapes only through the nose. For this to happen, two articulatory actions are necessary: firstly, the soft palate (or velum) must be lowered to allow air to escape past it, and secondly, a closure must be made in the oral cavity to prevent air from escaping through it.
/m/
The lips form a closure as for /p, b/, the soft palate is lowered, adding the resonance of the nasal cavity to those of the pharynx and the mouth chmber closed by the lips.
/n/
The tongue forms a closure as for /t, d/; the soft palate is lowerd, adding the resonance anasal cavity of the pharyncs and of that part of the mouth cahmber behind the alveolar closure; the lip position will depend on that adjacent vowels
/ ŋ /
A closure is formed in the mouth between the back of the tongue and the velum as for /k, g/; the soft palate is lowered, adding the resonance of the natural cavity to that of the pharynx and that small part of the mouth chamber ehing the velar closure, the lip position will depend upon that of the preceding vowel
