One person can enter a room, speak a few angry words, and quickly set everyone around him on edge. A few careless words between friends can be all that's needed to forever alter the tenor of their relationship. One derogatory word, which labels another person as slow, sloppy or spoiled, can make that perception true in the minds of all who hear it. Or, words can effect miracles. Words of encouragement can dispel despair, even for someone in a terribly difficult situation.
Words have the power to take what is ordinary and make it holy.
They turn a glass of wine into kiddush, and a man and woman into a couple united through the sanctity of marriage. Careful speech is the means G-d has given us with which to pursue peace with one another. When greeting an acquaintance, words can make that person feel sincerely acknowledged. When asking a child, a spouse or a colleague to perform a task, the words and tone can make the individual feel needed and appreciated. When it becomes necessary to reproach someone, words can convey loving concern for his welfare.