"Sit quietly and contemplate," said the Lama. "Get to know your anger, your fear, all your emotions. Dissect them and speak with them. Accept yourself and know every part of your own being. To understand oneself is to have compassion for everything."
Fasting from words, fasting from a volume of speech, being willing to humbly accept the yoke of silence and quietude deprives the tongue of the mastery of our hearts and minds. The tongue is a very useful tool for the art of love and for the art of prayer, but it is also the means by which we afflict others and even our own selves so often. So it must be called into holy obedience.