I can't verbally express a complicated thought very well. If I write it out on paper, I can actually see the words in front of me and then I can see if what I wrote is coherent. Perhaps that is why Tommy Jefferson(suspected of AS,) preferred to write political letters instead of give speeches. First of all, when I try and speak, I feel like I have a large wooden block in my tongue that prevents speech from coming out at all.
Once I get going, I noticed that if I have to describe something with more than a few sentences, I instantly dash for some profound detail and I tend to skip over some important points leading up to the climax. The listener is thus somewhat baffled and I have to backtrack and explain important information to help the listener make sense of what I said. I guess that I'm not sure sometimes what to tell people and what to leave out. I have a hard time bringing stories to a conclusion and I feel like I have to keep going and going and I can never really end it; after all, our lives don't just stop at the end of a poignant moment.
For example, If I was going to give someone a base, succinct overview of World War I, I would not just be able to give them 9 pithy sentences. I would spend 90 minutes discussing the campaigns and home-fronts and what not, but I would also digress and explain how the Franco-Prussian War and ethnic conflicts and other things built up to the war, and I would carry on and describe the Inter-War years up to WWII until my listener was thoroughly exasperated. At previous jobs, I would have to describe a simple situation and I would include details like a weather report and what everyone was wearing.
Sometimes, I have so much information to unload that the story I am trying to tell literally takes two hours and I just overwhelm the listener. I sidetrack onto unrelated tangents that tangle the basic plot. I just lose them in massive detail.