The Divine Institutes

But what account can we give of the voice? Grammarians, indeed, and philosophers, define the voice to be air struck by the breath; from which words derive their name: which is plainly false. For the voice is not produced outside of the mouth, but within, and therefore that opinion is more probable, that the breath, being compressed, when it has struck against the obstacle presented by the throat, forces out the sound of the voice: as when we send down the breath into an open hemlock stalk, having applied it to the lips, and the breath, reverberating from the hollow of the stalk, and rolled back from the bottom, while it returns to that descending through meeting with itself, striving for an outlet, produces a sound; and the wind, rebounding by itself, is animated into vocal breath. Now, whether this is true, God, who is the designer, may see. For the voice appears to arise not from the mouth, but from the innermost breast. In fine, even when the mouth is closed, a sound such as is possible is emitted from the nostrils. Moreover, also, the voice is not affected by that greatest breath with which we gasp, but with a light and not compressed breath, as often as we wish. It has not therefore been comprehended in what manner it takes place, or what it is altogether. And do not imagine that I am now falling into the opinion of the Academy, for all things are not incomprehensible. For as it must be confessed that many things are unknown, since God has willed that they should exceed the understanding of man; so, however, it must be acknowledged that there are many which may both be perceived by the senses and comprehended by the reason. But we shall devote an entire treatise to the refutation of the philosophers. Let us therefore finish the course over which we are now running.