language and thought

I've always wondered what language I think in, having been bilingual from a very early age, but much as I tried to "observe" my thought, I never could figure that out. I suspect I don't think in a language as much as in abstract concepts I am familiar with.

But here is something that says even those concepts could be influenced by my mother tongue: www.nytimes.com/2010/08/29/magazine/29language-t.html

Can you see how english (and even hindi) refers to my native language as "mother tongue", thus imparting a greater, nurturing quality to a language, making the concept of language more than just a means of communication?