Nasality in consonant articulation

Make the sound represented by <m> in the word Pam and continue it
for some seconds. As you continue it, pinch your nose and observe what
happens to the sound. It should stop immediately. This shows that air was
flowing through your nose as you produced this sound. Now try the same
little experiment with the <n> of pan and the <ng> of pang. You should find
that the air flows through the nose in these two cases also. Sounds in which
air flows through the nose are called nasal sounds. The air is allowed into
the nose by lowering the velum, the soft palate at the back of the mouth.
English has three main nasal sounds:

[m]                       Pam             clammy              mat

[n]                        pan              clannish              Nat

[N]                       pang             clingy