Consonants and Vowels.

If we regard the human voice as a continuous stream of air, emitted as breath from the lungs and changed into vocal sound as it leaves the larynx, this stream itself, as modified by certain positions of the mouth, would represent the vowels. "The vowels," as Professor Wheatstone says, "are formed by the voice modified, but not interrupted, by the various positions of the tongue and the lips." In the consonants, on the contrary, we should have to recognise a number of stops opposing for a moment the free passage of this vocal stream. These consonantal stops, against which the waves of the vowels break themselves more or less distinctly, are produced by barriers formed by the contact of the tongue, the soft palate, the palate, the teeth, and the lips with each other.