lei attending particularly to the phenomena of Speech, two things present themselves for consideration : in the first place, the various Sounds which compose it ; and, secondly, different Modes in which these sounds are be gun or ended.
The Sounds which enter into the composition of Speech may he arranged into two classes; and these we shalt distinguish by the terms laryngeal and oral.
Laryngeal Sounds are those which are produced en tirely by the larynx. Such, for example, are the sounds of the letters a, o, 1, n. A distinction exists among these, which, of course, is familiar to every one ; namely, some of them are Vocal sounds, or constitute what is called voice; others are Whispering sounds, and occur only in the isp er.
Both these kinds of sounds, without doubt, depend on vibrations produced in the expired air during its passage throuf.r,h• the larynx; though it is not easy to as certain the causes of the difference betwixt them. We may remark, however, that Vocal sounds arc susceptible, not only of various degrees of strength or loudness, ac cording to the different degrees of force with which the air is expelled from the lungs; but also of the greatest variations in tone, from changes in the dimensions of the windpipe, or varieties in the shape or size of the rims of the glottis. Whispering sounds, on the other hand, are susceptible of changes in point of loudness alone, with out the slightest perceptible variety in the quality of tone; and we are rather inclined to think, that the vibra tions on which they depend, are produced, not more by the aperture between the vocal chords, than by the other parts of the larynx. What is of more importance, how ever, to our present purpose to be known, is, that dur ing the production of every Vocal sound, a distinct vibra tion may he felt externally, by applying the fingers to that prominence on the fore and upper part of the neck which corresponds to the larynx, and which is often de nominated the pomum adami. But in the production of a Whispering sound, no such vibration can be per ceived.
It is not, however, by any changes of loudness or tone taking place in the larynx, that the Laryngeal sounds employed in Speech are so much diversified; but by differences in what we call, physiologically, their ex pression, and which depend on certain configurations vo luntarily given to the parts of the fauces and mouth, while the sounds are emitting from the larynx. We are
accustomed, in fact, to observe a very great uniformity in the tones and intensity of the sounds we employ in Speech ; but were we even disposed to introduce more variety in these qualities, still the Sounds would not un dergo any alteration of meaning ; unless they suffered at some time a change in their expression. The letter a, for example, may be sounded, in a whisper, or vocally, with the utmost variety of loudness, and on every tone of more than three octaves of the musical scale, and yet its signification remains unaltered; but the slightest change of expression converts it into a new sound, such as o, or n, or r, having a different name, and a different meaning.
There are twenty one Laryngeal sounds, all differing in expression from each other, employed in the English language. We shall consider each of these separately.
1. The sound expressed by the letter a in the words are and at. In the former of these words, the sound is expressed much more slowly than in the latter; in the one, tnerefore, it is said to be long, and in the other short. A long sound is usually pointed out by a straight line, drew,, above the letter or letters representing it, thus, art; and a short one, by a curved line, thus, cit. We shall employ these marks for the sake of brevity, in our future ii:ustratIons.
s(.9.-i,1 the. breath escapes entirely by the mouth, so that it ,::tonot be pronounced when the lips are shut. Its expression depends on a particular position of the back part of the tongue and the velum of the palate. We will not attempt to describe this ; but any one may observe it in himself by means of a mirror. The ex pression suffers no change, either by varying the position of the lips, or the teeth, or the tip of the tongue, or by shutting the nostrils.