Page:Popular Science Monthly Volume 9.djvu/419

Rh obstacles: thus are formed the sounds known as consonants. In setting up these obstacles, the tongue, the teeth, the lips, the soft palate, play respectively a more or less important part. We readily distinguish the labials, the linguals, the dentals, the nasals. No classification, however, will stand a rigid analysis; the simultaneous play of the teeth, tongue, lips, and soft palate, and the somewhat doubtful character of some sounds, render all classifications more or less arbitrary.

Among the consonants are the sounds of puffing, hissing, trilling, and these are pronounced without the aid of vowels. The labials are formed mainly by the movement of the lips—the easiest movement of all those concerned in the utterance of speech. Accordingly as the lips are closed tightly or loosely, two distinct letters are pronounced; if the closure is imperfect, a third letter is produced. There are two letters, m and n, which it is impossible to pronounce with the soft palate depressed, so as to close the nasal passages. Czermak introduced water into his nostrils, and then tried to pronounce these two consonants; the water was forced out by the passage of the air. The sound of the dentals is produced by a strong pressure of the tongue usually against the teeth, which, however, are not indispensable. The gutturals are pronounced by bringing the tongue back against the palate.

All these consonants may be classed, according to the character of the sound, as either surds or explosives. When the external air remains in communication with the air expired, notwithstanding the obstacle set up for articulation, the consonant may be sustained during the continuance of the expiration. Where there is no communication, the duration of the sound is restricted to the instant in which the obstacle is removed, and the result is a slight explosion of the air. This is shown conclusively when we precede a consonant with a vowel, and the same experiment serves clearly to show the distinction between hard and soft explosives. In pronouncing the former the glottic orifice is narrow, the current of air is feeble, and the sound persists for a moment after the mouth has opened; in the other case, the glottis allows the passage of a stronger current of air, and the sound has no perceptible duration.

Certain consonants are in English called trills; they are produced by the interruption of the breath at regular intervals, by vibrations of the soft palate and the extremity of the tongue. In the soft trill, the edges of the tongue produce simple oscillations of the air, but in the harsh trill, the vibrations produced at once by the palate and the tip of the tongue become intense. Finally, there are certain sounds of frequent occurrence in English, German, and the Slavonic languages; these are produced by an expiration differing from one