Internal monologue? Erm ... we all have one. Everyone here who speaks English, has an internal monologue where we think in English. If you learn another language, you'll learn that eventually, you will start thinking in that other language. I speak some German and a VERY little bit of Japanese. Whenever I start speaking (or trying to speak, haha) in those languages, I've learned to shift my mindset and start thinking *in* those languages, and that helps me speak much more fluently. So I don't know exactly what you mean by "internal monologue" ... sorry.
