Thats why Isaiah calls it an instructed tongue. Self-taught tongues build walls between people and destroy relationships. Tongues taught by the Spirit of God break down walls and repair broken relationships. He who guards his mouth and his tongue keeps himself from calamity. Wisdom dictates when, where and how hard we need to bite our tongues.
Wise people know there is a proper place, time and manner to speak the truth in love.
Don't be foolish and rush in where angels fear to tread. Carelessly speaking the truth has permanently fractured many relationships. When you are in the darkness the light of truth is needed. But may God have mercy on you if you strike a match when the atmosphere is saturated with emotional propane fumes. Often speaking the truth is an excuse to tell the other person what we think and feel about them.