having autism doesn't have anything to do with that
Formal speech patterns are often featured in people who have Asperger's Syndrome, though not always. This is actually described in the original instances of Asperger's Syndrome back at the Heilpadagogik Station (before it was bombed, of course)
Whilst Pecon speaks formally out of habit, the way I speak is the entire amalgamated library of all the words I've encountered and found intriguing, and in their respective sentance structures. Pecon actually commented on the way I spoke once and originally thought I was roleplaying some sort of robotic character, though I believe this viewpoint is no longer in place after a brief correction.
One article said that our viewpoint on written material can often be influenced by the way we read it. For instance, your mind might simulate a voice with various tone and pitch as you are reading, and what you are reacting to may be what your mind has simulated, as we often use 'sounds pretentious' rather than 'it reads as pretentious.' A certain percieved pattern of tone, pitch, and modulation would then fit into a stereotype, like the pretentious stereotype, though this depends on how your mind simulates the voice. We are right most of the time, but unfortunately, since I'm not actually pretentious, I get pigeonholed incorrectly, and often stay there.