Yes I tend to think in two languages but not at the same time. If I interact with someone in my native tongue, then I'm stuck in that "mode" until I read/listen/speak to someone in English. Then I start thinking in English. For the record, I'm more fluent in English even though I didn't speak a lick of it until age 10 or 11. Which language I speak in my dreams also tends to vary. If I'm speaking to someone (in a particular dream) who I believe speaks English, then I speak English. Vice versa.
This is really interesting to me because my dreams are all in French, regardless of who I am speaking with. I totally agree about being stuck in a 'mode,' I refer to it as my French brain, or my English brain (I have guarded in my mind Maori and English as the same language. I can't seem to break this). I am at the point where if someone that I normally speak English with, speaks French to me I find it incredibly difficult to engage my 'french brain' and speak French to them. It's so frustrating!
Yes, very similar. It's as though my mind sees the (normally) English speaker, and says "Right! Access all English words and semantics!" And everytime I go to retrieve French I have to actively think, make exact translations, double check my phrases. It's gets tiring, fast. Then, there will be someone right next to them, that I always speak in French with (and sometimes they are native English speakers, but we haven't spoken English together) and there isn't a split second where I think (actively) about what I say. It just flows out. And its so lovely and enjoyable.
Very similar for me. My native tongue is Spanish, but I learned English at age nine. If I'm listening to Spanish music, speaking Spanish with someone, etc. my thoughts happen in Spanish. Otherwise, I default to English in most settings. I can only pray in Spanish, though...seriously. It's super weird.
Can confirm: praying is definitely in Spanish. Also, for me, anything with numbers is in Spanish, even though I was taught mathematics in English. Weird.