In words are seen the state of mind and character and disposition of the speaker.  (Plutarch, 1st century Greek philosopher) 

Character and integrity are qualities that are developed over months and years of learning and experience. They are displayed by discipline, self-control, and interaction in community. One clear evidence of inner character is the outcome of dialogue—whether written or oral. The very words you use can be a mirror of your inner self. Be careful, O tongue, what you say!

The words of the godly are a life-giving fountain; the words of the wicked conceal violent intentions. (Proverbs 10:11)