I think the reason we stutter is because that when we hear ourselfs talk we get nervous and the mind automatically start stuttering for some reason, if you want to hear how fluent you are, you should put on a headset and blast music so loud (so that you can't hear yourself talking), and try reading out loud and record it, you will be completely fluent, try it out guys, and thats a prove thats it's a subconscious cause i think.