Organs of speech

Organs of speech

These can be divided in to three groups as below:
(i) Respiratory system
It comprises of:
 Lungs
 Muscles of the chest
 Wind pipe
Since people are well aware of these parts, no further details are necessary.
ii) Phonatory system
It comprises of:

(a) Larynx
These are two vocal cords that look like a pair of lips placed horizontally from front to back. It is located on top of the windpipe through which the air stream comes out after it is released by the lungs. They are joined in the front but separated at the back and the opening between the two cords is called „glottis‟.

The vocal cords are held loosely together. When air comes from the lungs, it is under pressure that vibrates the cords producing the sound. The frequency of the vibration is directly related to the number of times these cords open and close. Frequency of vibrations determines the pitch of the voice.

(b) Pharynx
It is a tube that begins just above the larynx. At the top, it is divided in to two parts, one part being the back of the mouth and the other being the beginning of the way to nasal cavity.
(iii) 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 in to 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, 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‟.

(b) The tongue

Surface of the tongue is divided in to four parts:
 The tip or the extreme end of the tongue
 The blade or the part that lies opposite the teeth ridge
 The front or the part that lies opposite to the hard palate
 The back or the part that lies opposite the soft palate
The tongue can take different positions to articulate different vowels and consonantal sounds.

Vowel sounds

There are 20 vowel sounds recorded. In the articulation of vowel sounds any part of the tongue can be raised towards the roof of the mouth. The tongue can be raised to different degrees for the articulation of different vowel sounds:

 Vowels for which front of the tongue is raised, are called „front vowels‟
 Vowels for which central part of the tongue is raised, are called „central vowels‟
 Vowels for which back part of the tongue is raised, are called „back vowels‟

In the production of vowel sounds, air stream comes out from the lungs continuously through the mouth and vocal cords vibrate. There is no closure of the passage nor there is narrowing of the passage.

Consonantal sounds

Consonantal sounds are produced because of the audible friction arising from the narrowing of passages for the exhaled air steam. Consonantal sounds are modified by the different positions of soft palate, tongue, lips etc. These sounds can be both:

 Voiceless
 Voiced

Whether it is voiceless or voiced depends upon the position of the vocal cords. When they are drawn close together, they vibrate and it is voiced. If they are drawn wide apart, they do not vibrate even when the air stream passes through them aggressively. Consequently they are voiceless.
Articulation of consonantal sounds

Three factors play important roles in the articulation of consonantal sounds:
 Place of articulation
 Manner of articulation
 Strictures

With these three variable factors, everyone can create very large array of ways of articulating words, phrases and sentences that would directly pierce through the heart of listeners.

(c) The lips
The lips play an important role in the articulation of some of the consonantal sounds. The lips can be:
 Tightly shut
 Brought together loosely

1. Drawn apart
2. Brought near to each other with a narrow gap in between

The lips also assume following positions for articulating vowel sounds:
 Spread
 Open
 Rounded
 Neutral