I've always thought in "associations" and I'm not sure how people think otherwise. When you say "think of a horse" I immediately consider all objects (as opposed to concepts, or people or other groupings I have) and separate a class labeled "horse", from the class "animal", and think of all the associations of that class.
It means that, when I think of "horse", I immediately think of things like "stallion" and "mare". I think of qualities of horses; "big" and "powerful" and "flappy gums". I also think of "donkey" and "zebra" and other animals of burden.
I don't think in language and I never have. I think this is because, growing up, I essentially learnt (during that pivotal period of time) two completely different languages so I quickly became aware of how language is just a tool and is completely unnecessary in thinking.
It's why I was a natural at logic. I think in "objects" or "classes" and what can be done to those objects...how they associate.
Interesting tidbit...all things that can be done to an object can be can done by adding it to another, comparing it to another, or considering its opposite. That is...negation, conjunction and disjunction completes all associations of any object. Something I needed to go to a logic class to figure out, but something that I couldn't believe I hadn't realized prior!
Unfortunately...when you get to thinking about all this...you realize just how useless thinking actually is. It's like...my thoughts think themselves at this point. So, I've moved on to other modes of interacting with the world.
Feelings, man. That stuff is tough.