"Language is the triumph of human ingenuity, surpassing even the intricacies of modern technology. It tells of widespread intelligence, sustained through scores of thousands of years. It is interesting that from the alternatives, sight and sound, sound was the medium first developed. There might have been a language of gesticulation. Indeed, there is a trace of it. But the weak point of gesticulation is that one cannot do much else while indulging in it. The advantage of sound is that the limbs are left free while we produce it.
"But there is a deeper reason for the unconscious recourse to sound-production. Hands and arms constitute the more unnecessary parts of the body. We can do without them. They do not excite the intimacies of bodily existence. Whereas in the production of sound, the lungs and throat are brought into play. So that in speech, while a superficial, manageable expression is diffused, yet the sense of the vague intimacies of organic existence is also excited. Thus voice-produced sound is a natural symbol for the deep experiences of organic existence."
(Alfred North Whitehead, Modes of Thought, NY: Capricorn, 1938, reprinted by Macmillan, 1958, pp. 44-45)