[breily]

I'd noticed this sometimes too, but I think it's something that you can change if you want to. When I was learning german, after a couple years of high school classes I went to a month long full immersion program. When I finished that, I was thinking entirely in german. This stopped over time as I went back to English, but I can still make myself do it sometimes. So with practice/time, you could probably teach yourself to think in something besides English. Though English seems like it might be the most efficient mode for a native speaker.