Speaking is thinking outloud. It is best to monitor some of your thoughts, the world is not a place to tell everything you are thinking, but it is also best not to mask too many of your thoughts. Your thoughts are telling you who you are, who you want to be, it is telling you to keep reading this, or to stop and go back to surfing videos of animal videos. It tells you when you want to go or stay, what you are thinking is basically your inner self, your true self at work. Its best to follow these thoughts, at least most of the time.

On occasion you might have a crazy thought. I once was holding a baby and had an awful though of throwing the child, it was a very quick and one-off though that I quickly dismissed but It stuck with me and I asked my father the next day if he thought I was crazy or if there was anything wrong with me. He went on to explain that we cannot control our thoughts and that sometimes we get crazy thoughts, that they are of course not meant to be acted on, but to observe them come and go is fine. Your thoughts will tell you what thoughts are the right ones and wrong ones, there are thoughts behind your thoughts. 

That we have an inner dialogue going on each day is also something to be dealt with. At times it is best to busy ourselves with sports, or tv or meditation, to quiet that voice. Too much of anything is too much, and to quiet the thoughts will relax you from time to time. It also gives your thoughts a time to settle down. To rest so they can become sharper, more adept to come out during conversation and better to help us navigate all the other thoughts and moments going on right outside our own universe. its best to speak the thoughts, best to let them rest and also best to subdue some all at the same time, a juggling mind game that requires rest from time to time, but not too much rest, we dont want them to atrophy.