them to vibrate up and down. This vibration makes sound. Take a thread, put
one end between your teeth, hold the other with thumb and finger, draw it
tight and strike it, and you will understand how voice is made. The shorter
the string, or the tighter it is drawn, the faster will it vibrate, and the
higher will be the pitch of the sound. The more violent the blow, the
farther will the string vibrate, and the louder will be the sound. Just so
with these vocal bands or cords. The varying force with which the breath
strikes them and their different tensions and lengths at different times,
explain the different degrees of loudness and the varying pitch of the
voice.

If the voice thus produced comes out through the mouth held well open, a
class of sounds is formed which we call vowel sounds.

But if the voice is held back or obstructed by the palate, tongue, teeth,
or lips, one kind of the sounds called consonant sounds is made. If the
breath is driven out without voice, and is held back by these same parts of
the mouth, the other kind of consonant sounds is formed.

The written word is made up of characters, or letters, which represent to
the eye these sounds that address the ear.

You are now prepared to understand us when we say that +vowels+ are the
+letters+ that stand for the +open sounds+ of the +voice+, and that
+consonants+ are the +letters+ that stand for the sounds made by the
+obstructed voice+ and the +obstructed breath+.

The alphabet of a language is a complete list of its letters. A perfect
alphabet would have one letter for each sound, and only one.