Based pronunciation standards of English

5)The organs of speech and their functions: Active and passive organs of speech; The articulatory mechanism and its work.
There are four cavities in out speech tract. They are: the nasal cavity, the mouth cavity, the pharynx and the larynx. They are empty spaces and function as resonators.
The organs of speech that can move and change their position are called active. They are: the lips, the tongue, the soft palate, the uvula, the vocal cords and the lungs. They take an active part in the articulation of speech sounds. They change the form and size of the resonators.
The lips change the shape and size of the mouth opening. They can be rounded or unrounded.
The bulk of the tongue can move horizontally and vertically. The movements of the tongue change the volume and the shape of the mouth resonator and different sounds are produced.
For the purposes of phonetics the tongue is divided into the following parts: the tip of the tongue, the blade of the tongue, the front of the tongue, the back of the tongue and the root of the tongue.
When the tongue is at rest, the blade with the tip lies opposite the alveolar ridge, the front of the tongue is opposite the hard palate, the back of the tongue is opposite the soft palate and the root of the tongue is opposite the back wall of the pharynx.
The soft palate with the uvula separate the mouth cavity from the nasal cavity. The uvula regulates the way of the stream of air in speech. When the uvula is raised, the stream of air goes out through the mouth cavity. When the uvula is lowered, the stream of the air goes out through the nasal cavity.
The vocal cords are the two muscles by the sides of the larynx. The space between the vocal cords is called the glottis. When the vocal cords are tense, they are brought close together, the stream of air touches them, makes them vibrate and they produce voice. When the vocal cords are lax, the stream of air goes out freely and no voice is produced; when they do not vibrate voiceless consonants are produced.
When we speak, the lungs push the stream of air out.
The passive organs are teeth, the alveoli and the hard palate. They are fixed and serve as places of articulation.
Speech is impossible without the following 4 mechanisms. The power mechanism. The diaphragm, the lungs, the bronchi, the windpipe, the glottis, the larynx, the mouth cavity, the nasal cavity. The functions: supplying in the form of air pressure, regulating the force of the air stream. The airstream provided by the lungs undergoes important modifications in other places of respiratory tract. The vibrator mechanism. It’s housed in larynx. When the air is exhaled from the lungs it’s led under the pressure into larynx through windpipe. Larynx is situated in the upper part of windpipe. The pitch of the voice is controlled by the tension of vocal cords. Voice produced by the vocal cords vibrations is modified by the shape and volume of the air passage. Each of the functions depends on the position and the shape of the glottis. In ordinary sp the glottis is freely open, the glottis is more opened in inhaling than exhaling. The resonator mechanism. Pharynx, larynx, mouth and nasal cavity. The air stream which has passed through the larynx is now subjected to further modifications acc to the shape assumed by the superglottal cavities. The obstructer mechanism. Tongue, lips, teeth, soft palate, uvula, hard palate, alveolar ridge. They serve to make some obstruction to the air stream. The 4 mechanisms work simultaneously and each speech sound is the result of their simultaneous work.