UNIT 1. THE PRODUCTION OF SPEECH. THE SPEECH ORGANS.
Speech sounds require that the speech organsshall be placed in certain definite positions or moved in certain definite ways. The main speech organs are the lungs, the larynx, the vocal cords, the palate, the tongue, the teeth and the lips.The most usual force of energy for our local activity is provided by an air stream expelled from the lungs.
The air-stream provided by the lungsundergoes important modifications in the upper stages of the respiratory tract before it acquires the quality of a speech sound.
First of all in the trachea or windpipe, it passes through thelarynx, containing the so-called vocal cords.
In using the vocal cords for speech, the human being has adapted and elaborated upon an original open-or-shut function. With the glottal stop (a glottalstop is a speech sound articulated by a momentary, complete closing of the glottis) in the back of the throat, the glottis may be held tightly closed, with the lung air pent up below it. This glottalstop frequently occurs in English, for example when it precedes the energetic articulation of a vowel or when it reinforces or even replaces /p/, /t/ or /k/. A glottal stop can be an allophone of /t/ infinal position, such as the "t" in habit or pat. In some dialects (e.g. Cockney and many other non-standard varieties) the glottal stop is also an allophone of /t/ in medial position, such as in theword bottle or fatter.
The glottis may be held open as for normal breathing.
The action of the vocal cords which is most characteristically a function of speech consists of their role as avibrator set in motion by lung air: the production of voice or phonation. In order to achieve the effect of voice, the vocal cords are brought sufficiently close together that they vibrate when subjected...