Persons idiotic from birth are incapable of producing any other vocal sounds than inarticulate cries, although supplied with all the internal means of articulation. Persons deaf and dumb are in the same situation, though from a different cause; the one being incapable of imitating, and the other being deprived of hearing the sounds to be imitated.
Fig. 153.—Direction of Pull of the Lateral Crico-Arytenoids, which adduct the Vocal Cords. (Dotted lines show position in adduction.)
In whispering, the larynx takes scarcely any part in the production of the sounds; the vocal cords remain apart and comparatively slack, and the expiratory blast rushes through without setting them in vibration.
In stammering, spasmodic contraction of the diaphragm interrupts the effort of expiration. The stammerer has full control of the mechanism of articulation, but not of the expiratory blast. His larynx and his lips are at his command, but not his diaphragm. To conquer this defect he must train his muscles of respiration to calm and steady action during speech. The stutterer, on the other hand, has full control of the muscles of expiration. His diaphragm is well drilled, but his lips and tongue are insubordinate.
355. The Care of the Throat and Voice. The throat, exposed as it is to unwholesome and overheated air, irritating dust of the street, factories, and workshops, is often inflamed, resulting in that common ailment, sore throat. The parts are red, swollen, and quite painful on swallowing. Speech is often indistinct, but there is no hoarseness or cough unless the uvula is lengthened and tickles the back part of the tongue. Slight sore throat rarely requires any special treatment, aside from simple nursing.
The most frequent cause of throat trouble is the action of cold upon the heated body, especially during active perspiration. For this reason a cold bath should not be taken while a person is perspiring freely. The muscles of the throat are frequently overstrained by loud talking, screaming, shouting, or by reading aloud too much. People who strain or misuse the voice often suffer from what is called “clergyman’s sore throat.” Attacks of sore throat due to improper methods of breathing and of using the voice should be treated by judicious elocutionary exercises and a system of vocal gymnastics, under the direction of proper teachers.
Persons subject to throat disease should take special care to wear suitable underclothing, adapted to the changes of the seasons. Frequent baths are excellent tonics to the skin, and serve indirectly to protect one liable to throat ailments from changes in the weather. It is not prudent to muffle the neck in scarfs, furs, and wraps, unless perhaps during an unusual exposure to cold. Such a dress for the neck only makes the parts tender, and increases the liability to a sore throat.
Every teacher of elocution or of vocal music, entrusted with the training of a voice of some value to its possessor, should have a good, practical knowledge of the mechanism of the voice. Good voices are often injured by injudicious management on the part of some incompetent instructor. It is always prudent to cease speaking or singing in public the moment there is any hoarseness or sore throat.