My writing is more straightforward and direct, although I can be just as blunt offline. A big difference is that I tend to be very tangential or circumstantial in my speech (as in the clinical definitions). Information is not organized in my brain as words (nor can I think in words - I have no "inner voice" or "inner monologue"), but as images and other sensory impressions, so I have to find ways to translate them into words in order to type them out or speak. With typing I tend to stop when I start to sidetrack, and I can see what I have already written to stay on course (but I still get sidetracked). When I speak I don't have any cues to keep me going, so whatever I am trying to talk about brings up associations and I talk about those, and it continues to spiral out of control until someone stops me or I realize what I am doing. If I do realize I may or may not be able to find my way back to where I started to continue my original point.
I also have issues with trauma and confrontation, such that angry people tend to trigger me and make it extremely difficult to be around or interact with them, even if they are not angry with me. This makes it even harder to communicate clearly face to face.
In speech I also rely heavily on scripts, memorized quotes from books, movies, television, things I have seen/heard others say, or things I have written out already. As such, novel topics can shut me down completely, or I end up on autopilot which may mean I will agree with something without understanding what I agreed with or to (and may very well disagree once I understand it).