Do you think primarily in English?
apu: I find that I use English for everything except 2 major classes of thoughts:1. Art. Specifically, if I'm trying to compare some work of art (music/movie/art), I have a virtual "media player/audiovisual search engine" in my mind that quickly lets me locate other works that are similar, related, or otherwise relevant. This similarity is often on the basis of the emotional content of the work, but I find that I don't need to put the concept into words to locate it. To use your example, if I'm looking at something that provokes empathy, I'll think of other works that provoke the same emotion, but without ever thinking of the word 'empathy' (or any synonyms/etc.).2. Science. If I'm trying to understand some scientific concept or if I'm working on something new (I'm a researcher), I find that I make almost no progress unless I can form a mental picture of the problem. Only after creating this picture can I do anything. Then most frequently I'll imagine myself "flying" through this mental model, tweaking it as I take into account various other factors, sometimes destroying parts and rebuilding, etc. Usually, I will come back to this same model over and over until finally I understand the concept or come up with some new realization.