Anger is like a dangerous and poisonous snake which is out of control. It frightens and hurts people and destroys everything in its path.
Some people are always getting angry. When they are angry they have no control over what they say. Words just pop out of their mouths - hurtful words that they might later regret. Since they are out of control, their words cause serious damage.
How can such a person stop speaking Loshon Hora? He must go right to the source of the problem and work on controlling his anger.