The psalmist knew the damage wrought by a false tongue, and knew what should be done about it,
“What shall be given to you, or what shall be done to you, you false tongue? Sharp arrows of the warrior, with coals of the broom tree!” (Psalms 120:3-4).
Do you hurt others by saying false things about them? Most of us would say no without realizing that we are misrepresenting someone.
Therefore, muse over your words about others before you speak them that you might never speak falsely.