Burning Lips or Learning Lips?

Proverbs 16:23 The heart of the wise teacheth his mouth,and addeth learning to his lips.
I heard someone say just the other day "If you have joy in your heart then please tell your face." Is this not what we are being taught here? It's the heart of the wise that is telling the mouth what to speak. It could be the lips have had to learn from the heart because more than once they have spoken words that have hurt instead of helping.