The heart of the wise teacheth his mouth, and addeth learning to his lips.
The heart of the wise teacheth (Hebrew, maketh intelligent - i:e., gives power of expression to) his mouth, and addeth learning to his lips. Wisdom in the heart suggests to the mouth what, how, where, and when one ought to speak. Each one is eloquent enough in that which he understands. During speaking "the heart of the wise addeth learning to his lips" - i:e., suggests ever fresh conceptions and learned thoughts to be uttered by the lips.