Insulting Behaviour

Part of being human is being able to speak and form coherent words from our thoughts. Animals work on impulse and instict, never stopping to think what they are doing or the reason for their behavior. It is so much easier to be able to insult someone without being able to say something intelligent. There is a lack of imagination and creativity when a person insults someone else. I have found myself repeatedly insulting someone very close to me and I don't know how to stop. The insulting words just pop out of my mouth without my knowing. After they have done their damage it is too late to recall them. I have heard of the wise saying, "Think before you speak," but how do I impliment that type of thinking in my life? I don't know that an insult is forming; I don't wish to inflict harm. My creative juices are impeded by insulting thoughts. I lack the creativity to make intelligent conversation. Should I be held accountible because G-d has not given me intelligence? I don't want to place the blame solely on G-d but I am at my wits end on how to make intelligent conversation with close family and friends. Any suggestions?