"In the multitude of words there wanteth not sin: but he that refraineth his lips is wise." - Proverbs 10:19
It's always safer to refrain from speaking. Of course, we must speak when God prompts us to speak, and there is a world of difference between God-incited words and self-incited words. We know when God is prompting us to speak; for it is usually difficult and frightening, and is certainly always honoring to Him and edifying to the listener. But when we speak from the selfish impulses of our sinful hearts, it is usually self-glorifying and destructive to the listener.