The first step in spiritual discipline (Sadhana) is the cleansing of the speech. Talk sweet without anger. Do not boast of your scholarship or attainments. Be humble, eager to serve; conserve your speech; practice silence. That will save you from squabbles, frittering thoughts and faction. When the heart is free from agitation, the tongue is dumb and the ear has rest. You are where your mind is, not where your body rests.
(From : Sai Veda, The Word of God, sayings of Bhagavan Sri Sathya Sai Baba)