The book of James teaches us a lot about the tongue.
My brethren, let not many of you become teachers, knowing that we shall receive a stricter judgment (James 3:1). You will have to give an account for the things you say.
Look also at ships: although they are so large and are driven by fierce winds, they are turned by a very small rudder wherever the pilot desires (James 3:4). The same way the rudder drives the ship, the tongue drives the body.
With it we bless our God and Father, and with it we curse men, who have been made in the similitude of God. Out of the same mouth proceed blessing and cursing. My brethren, these things ought not to be so. (James 3:9-10)
We can speak blessings or curses with our tongue.
This is why we must rule our spirit and live in surrender to Jesus.