Like many others, my thinking is also internal discussions, whether with just one voice or multiple. The interesting thing to me is that while in my mind these 'discussions' feel complete and like regular conversation, when it comes to verbalise them I find quite often there's huge and often unjustifiable gaps and leaps in the thinking. If discussing a problem with a colleague, I'll often find that either the answer is obvious, or often that I need to take more time to come up with a coherent way of explaining it.

I don't do it often enough, but often I try to safeguard against this when coming to conclusions by forcing myself to say them aloud.