Either I'm a politely awkward and shy, or I ramble, the way a typical geek does. I am not very adept in social situations as of yet, though I intend to remedy this after I go to college, and I fall into the habit of trying to word something that is rather unpleasant in the most diplomatic (and usually long-winded) way possible. Unfortunately, while one can hardly tell the difference when I put such strategy to practice on the forums, it takes me forever to actually get the words out when talking in real life... so its probably not hard to tell when I feel insecure about a certain subject. I'm often complimented on my vocabulary, but I personally believe the occasions for these compliments are rather trivial. The internet is a better testament to my vocabulary, just as it has been noted by many that have posted here.
I can be random however around those I know, and quote movies or old sitcoms frequently even when I know no one will get the in-joke (which only makes it more funny to me).
As for specific speech peculiarities, transitional phrases such as "that is to say" are rather common along with the classic "um". Around my siblings, I shout easily, but don't usually have the patience to deliver a proper lecture.