The Organs of Speech and their Functions

Lecture No.2
Title:The organs of speech and their functions
Speech is produced in the throat, mouth and nasal passage, but there are no “speech organs” as such, strictly speaking; all of the organs used in speech have other, and perhaps more fundamental, purpose involving eating and breathing. Nevertheless the term is familiar and meaninful in the contex of articulatory phonetics, and will be used here.
The lungs, diaphragm, chest muscles and windpipe act in the production of speech. Speech is produced by causing a column of enclosed air to v?brate. It is the same process, basically, as the production of sound by a wind instrument in music. Air is forced under pressure from the lungs trough the windpipe (trachea), to the voice box (larnyx), a structure that sits on top of the windpipe and contains the vocal cords, as they are called. (These are not cords at all, and would be more properly named band s or membranes). The vocal cords have the capability of closing off entirely the opening (glottis) and can hold considerable air pressure (as when a person coughs or strains to lift a heavy weight). They can also assume other positions. They may be wide open, allowing the air to pass unimpeded. Or they may be closed almost but not quite completely, so that the escaping air, forced through the narrow opening between them causes them to v?brate like the reed in a musical instrument. This vibration makes the all-important vocal tone. known technically as voice, without which speech would be impossible. Speech sounds that have this tone as part of their makeup are called voiced., and those without it are called unvoiced or voiceless. Varying the amount of tensi?n on the vocal cords causes the vocal tone to vary in quality and in number of cycles per second; in other words, the timbre and pitch of the tone can be changed voluntarily, within limits by the speakers.
The air stream issuing from the larynx w ith or without voice, can now be modified in many ways; that is, we are at the stage of articulation. Almost all the parts of the throat and lower head that are accesible to the air stream can take part in articulation. .