General classification of speech sounds

Speech sounds are broadly divided into two categories, namely, Vowels and Consonants. If we say the English word shoe, we realize that this word is made up of two sounds, one represented by the letter sh and the letter oe. When we produce the word represented the letter sh slowly, we realize that during the production this sound, the air escapes through the mouth freely and we do not hear any friction. The sound that is represented by the letter sh in the word shoe is a consonant and the sound represented by the letters oe in the word shoe is Vowel. (All sounds during the production of which we hear friction are consonants, but not all consonants are produced with friction).

If we say the words she, shoe, shy, show, ship and shout, we will realize that when we produce the sounds represented by the letters e, oe, y, ow,i and ou in these words, the air escapes through the mouth freely without any friction. All these sounds are therefore vowels but each one of them sounds different form the others. These sounds should therefore be sub-classified. Similarly, if we say the words shoe, see, zoo, and who, we will hear friction during production of the sounds represented by the letters sh, s, z and wh. All the se sounds are therefore consonants. But once again we will see that each of them sounds different from the others. The sounds that are called consonants also need to be sub-classified. In the chapter we will take up the classification and description of consonants.

To describe a consonant sound, we need certain important pieces of information. We need to know the following regarding its production:

- the air stream mechanism;

- the state of the glottis;

- the position of the soft-palate;

- the active articulator;

- the passive articulator;

- the stricture involved.

The air –stream mechanism: All English sounds (vowels as well as consonants) are produced with a pulmonic egressive air-stream mechanism, i.e., lung-air pushed out.

The state of glottis; Speech sounds can be classified voiceless or voiced, depending upon whether the vocal cords are wide apart and the glottis is wide open (voiceless) or the vocal cords are kept loosely together and they vibrate (voiced).

The position of the soft-palate; Speech sounds can be classified as oral or nasal, depending upon whether the soft-palate is raised so as to shut off the nasal passage of air (oral) or it is lowered to open the nasal passage of air simultaneously with an oral closure (nasal). Sounds can also be nasalized.

And (e) The active and passive articulators: Of the various articulations described, at least two are required for the production of any speech sound; some articulators move during the production of speech sounds. These are termed active articulators. Certain other articulators remain passive and the active articulators move in the direction of these. These are termed passive articulator. The lower tip and the tongue are the active articulators. The upper lip and the entire roof of the mouth are the passive articulators. It should be remembered, however, that the upper lip and the soft palate are capable of independent movement; but when either of these is one of the articulators involved in the production of a sound, it is always the other articulator (the lower lip in the case of the upper lip and the back of the tongue in the case of the soft palate) that moves towards these. So the upper lip and the soft palate are considered passive articulators.