Derrida was a badass. Didn't he just die like a couple of years ago? Anyways, communication without verbal language. Telepathy, maybe? Other than that, I can't really think of a way. Here's an interesting question, though. Are stimuli necessary for thoughts to occur? In other words, do I need to experience something in order to think? If so, that's a pretty strong argument for determinism, isn't it? In order to have free will, it seems, we would need to have original thought.