Just as eloquence, unenlightened by reason, is rash and blind, so wisdom, without the power of expression, is feeble and maimed. Speechless wisdom may sometimes increase one’s personal satisfaction, but it rarely and only slightly contributes to the welfare of human society. Reason, the mother, nurse, and guardian of knowledge, as well as of virtue, frequently conceives from speech, and by this same means bears more abundant and richer fruit. Reason would remain utterly barren, or at least would fail to yield a plenteous harvest, if the faculty of speech did not bring to light its feeble conceptions, and communicate the perceptions of the prudent exercise of the human mind. Indeed, it is this delightful and fruitful copulation of reason and speech which has given birth to so many outstanding cities, has made friends and allies of so many kingdoms, and has unified and knit together in bonds of love so many peoples.
~John of Salisbury, The Metalogicon, Book I. Chapter 1.