Ephesians 4:29 (ESV) - Let no corrupting talk come out of your mouths, but only such as is good for building up, as fits the occasion, that it may give grace to those who hear.
Colossians 3:8 - But now you must rid yourselves of all such things as these: anger, rage, malice, slander, and filthy language from your lips.
Psalm 19:14 - May the words of my mouth and the meditation of my heart be pleasing in your sight, O LORD, my Rock and my Redeemer.
James 5:12 - Above all, my brothers, do not swear—not by heaven or by earth or by anything else. Let your "Yes" be yes, and your "No," no, or you will be condemned.
Ephesians 5:3-7 - But among you there must not be even a hint of sexual immorality, or of any kind of impurity, or of greed, because these are improper for God's holy people. Nor should there be obscenity, foolish talk or coarse joking, which are out of place, but rather thanksgiving. For of this you can be sure: No immoral, impure or greedy person—such a man is an idolater—has any inheritance in the kingdom of Christ and of God. Let no one deceive you with empty words, for because of such things God's wrath comes on those who are disobedient. Therefore do not be partners with them.
Ephesians 4:31 (ESV) - Make a clean break with all cutting, backbiting, profane talk.
Colossians 4:6 (MSG) – Be gracious in your speech. The goal is to bring out the best in others in a conversation, not put them down, not cut them out.