Articulatory system

Articulatory system

It comprises of the nose, the mouth including the teeth, the tongue, the soft palate, and the lips. The roles of the palate, the tongue, and the lips are described below:

(a) The palate

The roof of the mouth can be divided into three parts:
Teeth ridge or the alveolar ridge – It is the part just behind the teeth. It is the hard convex surface behind the upper front teeth.
The hard palate – It is the hard concave surface the follows the teeth ridge
The soft palate or the vellum – The back part of the roof is called the soft palate
The soft palate can be lowered to close the nasal passage.
When nasal passage is closed, sounds are produced with the escape of air stream through the oral passage. These sounds are called oral sounds. Excepting sounds for „m‟, „n‟ and „r‟, all other sounds are „oral sounds‟.

When the nasal passage is opened and simultaneously, the oral passage is closed by closing the lips or part of the tongue making a firm contact with some part of the roof of the mouth, the air stream coming from lungs passes through the nasal passage and makes „nasal sounds‟.
When both oral and nasal passages are open for the air stream from lungs to escape, the sounds thus produced are called „nasalized sounds‟.