The Bible says in Proverbs, Chapter 25, Verse 11. A word fitly spoken is like apples of gold in pictures of silver. That means that we can either encourage and help the person that hears our words or discourage and destroy the person that the words are spoken to.
I'm going to give an example on how a persons words can really affect someone: I had a friend that had a Facebook and she was talking to this boy that she liked and was friends with on it. She had personally known this boy for years and they normally never fought, ( at least not around me). One day she decided, that she would relate to him how she had felt about him, by telling him that she liked him. He responded in the wrong way by saying, I don't like you and never will like you, so you should just go commit suicide. (There is more to what he said, but I'm not going to add any details). After reading this, her heart broken, she did just that, she ended her life. Now lets look at it like this. What if that boy could have handled the situation in the right way and said, I don't have the same feelings towards you as you do me, I'd rather us just be friends. She might still be alive today. After finding out about her death, he was sorry, but it was to late.
What I am trying to say is, words are powerful. What we say to others can affect them either in a positive way or a negative way.
Now, you can do what ever you want with this, your words can either bring happiness or sadness, respect or disrespect, or in some cases like the one above life or death. Just remember all of the times that we have put a smile on someone's face and let us also recall the times when we have seen others walk away in tears, because of our choice of words. So let us let every word that comes out of our mouth be used with caution and kindness and at the very least our conscience will be clear.