This describes my experience nicely too, although I didn't quite realize it until reading this. I was thinking I just thought in words and had a tendency to mix up the bits of various languages I know some words from, but occasionally I have some thought, then for one reason or another become conscious of the thought and get confused which language I was thinking in. Sometimes this even manifests as trying to mix languages (eg at one point I used to struggle to not sprinkle in french and farsi words into normal english, despite speaking english at a native level and only knowing the basics of the other two).
I've always thought of my mental model as an endless conversation with myself, but I think the more fitting description would be a "smooth" series of thoughts which only materialize into language when I explicitly focus on those thoughts as their own thing.
I do also think visually for things that have a visual component though.