Jewish sources define the human being as "the speaker". The ability to communicate is central to human function. Speech allows us to express our feelings, develop our emotions, explain concepts, influence other people and strengthen relationships.
But speech can be destructive. Negative talk can hurt and have a lasting effect. Gossip can ruin reputations and cause irreparable damage. The saying we were taught as children - "sticks and stones can break my bones but words can never hurt me" - is simply untrue. We can usually recover from physical injury quite quickly, but it takes a lot longer to heal the wounds of insulting and hurtful words.
Jewish sources offer an analogy to remind us to always use the power of words positively. Speaking is like riding a race horse. We are the rider and the words we say are the horse. If we can control the horse it will allow us to travel with amazing speed and reach destinations that would otherwise be impossible. But if we lose control and the horse runs wild, we could be thrown and suffer terrible injury.
The stronger the horse, the greater the speed will be and more ground can be covered, but so does the potential harm grow. It all depends on control - does the rider control the horse, or has the animal gained the upper hand?
Speech is the one of the greatest Divine gifts given to mankind. Use it well.