Temple Grandin is a PhD and a leading designer of slaughterhouses. She is also autistic. You can read a fascinating first-person discussion of her method of processing thought and language here:

http://www.grandin.com/inc/visual.thinking.html

And here is an excerpt:

Autistics have problems learning things that cannot be thought about in pictures. The easiest words for an autistic child to learn are nouns, because they directly relate to pictures. Highly verbal autistic children like I was can sometimes learn how to read with phonics. Written words were too abstract for me to remember, but I could laboriously remember the approximately fifty phonetic sounds and a few rules. Lower-functioning children often learn better by association, with the aid of word labels attached to objects in their environment. Some very impaired autistic children learn more easily if words are spelled out with plastic letters they can feel.
Spatial words such as "over" and "under" had no meaning for me until I had a visual image to fix them in my memory. Even now, when I hear the word "under" by itself, I automatically picture myself getting under the cafeteria tables at school during an air-raid drill, a common occurrence on the East Coast during the early fifties. The first memory that any single word triggers is almost always a childhood memory. I can remember the teacher telling us to be quiet and walking single-file into the cafeteria, where six or eight children huddled under each table. If I continue on the same train of thought, more and more associative memories of elementary school emerge. I can remember the teacher scolding me after I hit Alfred for putting dirt on my shoe. All of these memories play like videotapes in the VCR in my imagination. If I allow my mind to keep associating, it will wander a million miles away from the word "under," to submarines under the Antarctic and the Beatles song "Yellow Submarine." If I let my mind pause on the picture of the yellow submarine, I then hear the song. As I start humming the song and get to the part about people coming on board, my association switches to the gangway of a ship I saw in Australia.

I also visualize verbs. The word "jumping" triggers a memory of jumping hurdles at the mock Olympics held at my elementary school. Adverbs often trigger inappropriate images -- "quickly" reminds me of Nestle's Quik -- unless they are paired with a verb, which modifies my visual image. For example, "he ran quickly" triggers an animated image of Dick from the first-grade reading book running fast, and "he walked slowly" slows the image down. As a child, I left out words such as "is," "the," and "it," because they had no meaning by themselves. Similarly, words like "of," and "an" made no sense. Eventually I learned how to use them properly, because my parents always spoke correct English and I mimicked their speech patterns. To this day certain verb conjugations, such as "to be," are absolutely meaningless to me.

I tend to combine the verbal and visual when I think, and tend to store information as a conclusion for which I then have to consciously search for the supporting facts.

What about you?