The lips can be closed, or kept lightly touching, or the lower lip may touch the upper teeth; or the lips may be apart, assuming various shapes, from a narrow slit to a large or small circle. They may also be thrust forward, protruded.
The tongue is capable of an even greater variety of position. Again watch the inside of your mouth by means of your little mirror. Say e (as in he), a (as in father), o (as in who), and observe the movements of your tongue; then make the same movements, but without uttering the sounds. You will soon feel how your tongue moves, without needing to look at it. This consciousness of the muscular action of your tongue is valuable, and you must take pains to develop it. Watch the movements of your tongue as you utter other vowel sounds; they will be treated systematically in due course.
By means of these movable organs of speech the mouth passage assumes various forms; it may still be wide enough to leave a free course for the breath, or it may be quite narrow, or it may be closed at some point.
If the passage is free, the result is a vowel; if not, it is a consonant.[8]
10. If the passage is so narrow at some point that the breath cannot pass through without rubbing or brushing, we have a continuant (sometimes called a fricative). Thus when we say f or v, the breath passes out through the teeth; the only difference between the two sounds being that in saying v, the breath is also engaged in setting the vocal chords vibrating. Say e (as in he) and gradually raise the tongue still further, thus narrowing the passage; you will reach a point when you no longer produce a vowel, but a continuant, namely the sound heard at the beginning of yes. These sounds are called continuants, because we can prolong them at will; indeed, we can dwell on them until no more breath is left in the lungs.
11. If the passage is closed altogether at some point, we have a stop; the breath is stopped. Say hope or wit or luck and notice how in each case there is a closure at the end. Stops consist of two parts: the closing of the passage, and the subsequent opening of it; this opening resembles a little explosion, and stops are accordingly sometimes called plosives or explosives. Observe that the ear does not require to perceive both the closure and the opening; one is enough to give the impression of the sound. When you say hope or wit or luck, you need only hear the closing of the passage; you can leave your mouth shut, yet to the ear the word will seem complete. (The sound will, however, carry further if you open the passage again; and in public speaking it is therefore to be recommended.) Similarly, in uttering the words pain, tell, come, only the opening of the passage is audible; yet the ear is satisfied. In the middle of a word like night-time, carefully pronounced, we hear both the closure and the opening; and the interval between the two gives our ear the impression that there are two t's.[9] In quick speech, however, the closure is usually inaudible in such words or, more correctly, the sounds overlap.
12. The narrowing or closing of the passage may be effected at various points. The lips may be partially or completely closed; the lower lip may be pressed against the upper teeth; different parts of the tongue may be pressed against the teeth, or the gums, or the palate. Pass your finger along the roof of your mouth, and notice that only the front of it is hard; we distinguish the hard palate and the soft palate.
13. When we are eating or drinking, the food passes down the gullet, behind the windpipe. To prevent food entering the windpipe, which causes a choking sensation and coughing, there is the epiglottis (see the diagram on p. [10]), a cartilaginous flap which covers the top of it; this flap is raised when we are breathing. Hence the wisdom of the rule, not to speak while you are eating.
14. In order that speech may have its full effect, it is necessary that the hearer should hear well; this is by no means so common as is generally supposed. The importance of testing the eyesight is now recognised; but the hearing is usually neglected. Attention must be drawn to this matter, as teachers often regard pupils as inattentive and dull and reprimand them, when they are really hard of hearing. The teacher's mistake is to some extent pardonable, because the defect is easily overlooked, especially as a pupil may hear badly in one ear and not in the other, and thus seem inattentive only when the teacher happens to be standing on the side of his defective ear. Further, it is a defect which often varies in intensity from day to day, according to the pupil's general condition of health. These considerations point to the urgent necessity of instituting an inspection of the hearing in our schools. The teacher can himself apply the simple test of seeing at what distance the pupil is able to hear whispered double numbers, such as 35, 81; each ear should be tested separately, a cloth being pressed against the other. The teacher will note down the two distances for each pupil, and will probably be surprised at the variations observed. It is clear that defective hearing should constitute a strong claim for a front seat in the class-room, more so than defective eyesight, which can usually be rectified by the use of suitable spectacles.
It is hardly necessary to point out that lack of cleanliness in the ears may interfere with the hearing, and that carelessness with regard to the teeth may lead to their loss and to defects of speech, apart from other unpleasant consequences. It is clear that anything in the nature of tight-lacing renders good breathing impossible; and the fashion of letting the hair cover the ears is also to be discouraged, as rendering the hearing more difficult. In men, tight collars and belts often interfere with the breathing.