Emil Behnke, The Mechanism of the Human Voice
“ The lungs, as we have seen, are the bellows of our vocal organ; they supply the air which is the motive power on which the voice depends. Without air no tone can be produced. Nay, more, life itself must cease without it. Breathing goes on regularly while the voice is silent; but in speaking and singing both inspiration and expiration have to be regulated according to the nature of the phrases to be spoken or sung. If the speaker does not know how to take breath and how to control the expiration, his delivery will of necessity be jerky and uncertain. ”
