This indicates a fear that someone will publish secret aspects of your personality, or reveal hidden truths you know. It may be a warning from the unconscious to be prudent and not talk too much.
Gallery of dreams
Do animals dream?
Research conducted by various scientists show that animals do experience dream while sleeping. They also experience similar sleep stages like human beings - REM and Non-REM. If you have noticed a dog sleep, it might sometimes wag its tail, this indicates some response to its dream. A study was conducted in a cat by removing a part of the brain stem, which will not prevent it from reacting to the dream during REM. It was noted in some cats they were aggressively chasing mice as in reality.
Reading in dream
Sometimes you will not be able to differentiate lucid dream. If you want to be sure, try reading a simple sentence, if you are able to read then you are in wakeful stage if not you are in lucid dreaming. Studies show that you cannot read while dreaming or you will not find the repeated sentences one more time.