It is just fear. You just stutter whenever you let fear control you. If you feel comfortable in a particular situation, you will not stutter because you don't fear. Fear is not a feeling but a spirit according to the Bible: <<For God hath not given us the *spirit of fear*; but of power, and of love, and of a sound mind.>> (2 Timothy 1:7 KJV) So, it is all about spiritual warfare. Everything starts in the mind. Pay attention to your thoughts before speaking. It took me several years to realize what was going on in my mind. It took me a lot of time to recognise the influence of the spirit of fear in my mind before I started speaking. A single negative thought can tear you down. The mind is the battlefield. Evil spirits act in the shadow by sending negative thoughts to us through our mind. We need to strengthen our spiritual armor so that evil spirits can do nothing to us. If we doubt or let fear control us for just one second, we end up stuttering. The life of a stutter is very similar to Peter trying to walk on the water. Read Matthew 14:22-33 With trust and love we can conquer the spirit of fear. The devil can do nothing to us if we love: <<There is no fear in love; but perfect love casteth out fear: because fear hath torment. He that feareth is not made perfect in love.>> (1 John 4:18)