The Work of the Organs of Speech

Date: 2015-10-07; view: 504.

In accordance with their linguistic function the organs of speech may be grouped as follows:

The respiratory or power mechanism furnishes the flow of air which is the first requisite for the production of speech sounds. This mechanism is formed by the lungs, the wind-pipe and the bronchi. The air-stream expelled from the lungs provides the most usual source of energy which is regulated by the power mechanism. Regulating the force of the air-wave the lungs produce variations in the intensity of speech sounds. Syllabic pulses and dynamic stress, both typical of English, are directly related to the behaviour of the muscles which activate this mechanism.

From the lungs through the wind-pipe the air-stream passes to the upper stages of the vocal tract. First of all it passes to the larynxcontaining the vocal cords.The function of the vocal cords consists in their role as a vibratorset in motion by the air-stream sent by the lungs. At least two actions of the vocal cords as a vibrator should be mentioned.

The opening between the vocal cords is known as the glottis.When the glottis is tightly closed and the air is sent up below it the so-called glottal stop is produced. It often occurs in English when it reinforces or even replaces [p], [t], or [k] or even when it precedes the energetic articulation of vowel sounds. The most important speech function of the vocal cords is their role in the production of voice.The effect of voice is achieved when the vocal cords are brought together and vibrate when subjected to the pressure of air passing from the lungs. This vibration is caused by compressed air forcing an opening of the glottis and the following reduced air-pressure permitting the vocal cords to come together again.

The height of the speaking voice depends on the frequency of the vibrations. The more frequently the vocal cords vibrate the higher the pitch is. The typical speaking voice of a woman is higher than that of a man because the vocal cords of a woman vibrate more frequently. We are able to vary the rate of the vibration thus producing modifications of the pitchcomponent of intonation. More than that, we are able to modify the size of the puff of air which escapes at each vibration of the vocal cords, that is we can alter the amplitudeof the vibration which causes changes of the loudnessof the sound heard by the listener.

From the larynx the air-stream passes to supraglottal cavities,that is to the pharynx,the mouthand the nasalcavities. The shapes of these cavities modify the note produced in the larynx thus giving rise to particular speech sounds.