I'm pretty much the same, but my internal monologue sometimes manifests itself as, I don't know how to describe it, but, as "feelings". This is somewhat usefull, but I need a more formal method sometimes to explain me to myself.
When I am thinking about something new there are no words, images, etc. just feeling my way through ideas. It feels kind of like acting on instinct. For example if I am wrestling with an idea I get an impression of "resistance". Feeling my way through the path of least resistance from impression to impression.
I do say words, or see flashes of images but only for ideas that I have already felt out. Words are kind of a breadcrumb trail so that I can retrace the exact train-of-thought that I had taken before and images like mile-markers.