When words are many,
sin is not absent,
but he who holds his tongue
Proverbs 10:19 (NIV)
Some people just need to learn to shut-up.
Close your mouth, zip the lip, say no more!
Between the mouth and the brain there is a flow valve. The brain thinks something, and the valve decides whether or not to let it pass to the mouth. Some people have non-functional valves. Thoughts just flow right out of the mouth: Some good, some bad, some ugly.
The most interesting thing about these people who don't know when to be quiet, is that you really get to know who they are. Jesus put it this way, "...out of the overflow of the heart, the mouth speaks." When something spills out, saying, "oops, I didn't mean that..." isn't exactly true. The truth is: you said exactly what you meant.