LETTERS exn ARTICULATE SOUNDS. Letters are conventional marks or visible signs of the elemental sounds of spoken language. The earliest symbols of sounds repre sented syllables rather than simple sounds (see ALPHABET, HIEROGLYPHICS, CHINESE LANGUAGE). It was only gradually that syllables were reduced to their ultimate elements, and all alphabets yet bear marks of their syllabary origin (see- letter K), displaying various imperfections both of excess and defect.
Articulate sounds are divided into vowels and consonants; rad the latter are subdi vided into voiceless and vocal elements (otherwise called "sharps" and "flats"), obstruc tive and continuous elements (otherwise called " mutes" and " semi-vowels"), and liquids. Many other divisions have been proposed, but the above classification embraces all real varieties. The elements are likewise classified according to the organs which form them, as labials, linguals, gutturals, nasals, etc. A physiological description of the articulate sounds used in English speech, will show the necessary extent of a perfect system of letters, and exhibit the short-comings of our present alphabet.
All the elements of speech are susceptible of separate formation; and in the following description, reference is always intended to the exact sound of each element, and not to the names of the letters.
Emitted breath mechanically modified forms every articulate sound. The breath is first modified in the throat, by a certain amount of constriction in the larynx, wanting which restraint, the air would flow out noiselessly, as in ordinary breathing, or gushingly, as in sighing. The breath is thus economized into a steady stream, and rendered audi ble by the degree of roughness or " asperation" it acquires when forced through a narrow aperture. This "asperated " current of air, when articulated, forms whispered speech. In passing through the larynx, the breath is further acted on by the opposing ligaments of the glottis (the aperture of the larynx), and sonorous voice is produced. The vocal ized or asperated breath receives vowel and articulate modification in its passage through the mouth. When the mouth is sufficiently opelb to allow the breath to flow without
obstruction or oral asperation, the air is molded into the various qualities of vowel-sound; and when the channel of the mouth is obstructed, or narrowed so much .as to cause a degree of asperation of the breath between the tongue and the palate, the lips, etc., con are produced.
The upper part of the mouth is an immovable arch: all variations in the shape of the oral passage are consequently effected by the tongue and the lips. [A nasal -variety of vowel-sounds occurs in Freneh—represented by n after the vowel-letters. These sounds are formed by depressing the soft palate, which otherwise covers the inner end of the nostrils, and allowing part of the breath to pass through the nose, while the remainder is modified in the usual way.] Vowels. —When the tongue is raised in its greatest convexity towards the roof of the mouth, but without being so close as to roughen or asperate the breath, the resulting vowel quality is that heard in the word eel; and progressively less degrees of elevation produce a series of lingual vowels, of which Alt is the most flattened—the lips being equally expanded throughout the series, to allow the breath to escape without labial modification.
When the aperture of the lips is contracted in the greatest degree short of asperating the breath, the resulting vowel-quality is that heard in the word ooze; and progressively less degrees of labial contraction form a series of labial vowels, of which Aw is the most open—the tongue being retracted throughout the series, to direct the breath without lingual modification forward against the lips.
A. third series of vowels is formed by combining elevated positions of the tongue and contracted positions of the lips, or retracted positions of the tongue, and expanded posi tions of the lips. Of this labio-lingual series, the German 22 is the most contracted, and the English sound heard in the word err the most open.