On a bit of a roll here. Patchen reproduced this one in Comments a while back, and bicentennial celebrations can bring it out into the light:
The urge to communicate must have been the original motive for human beings who were still alone to announce their existence to living creatures outside themselves, especially to those which emit sounds which can be imitated and which can subsequently serve as a name. A similar effect of this urge can still be seen in children and thoughtless people who disturb the thinking section of the community by banging, shouting, whistling, singing, and other noisy pastimes (and often even by noisy religious devotions). For I can see no motive for such behaviour other than a desire on the part of those concerned to proclaim their existence to the world at large.
From the “Conjectures on the Beginning of Human History”.