As we all know that our mother tongue is our language & very much guiding force for the development of our childhood with the passage of time for our advance studies & our career we study in generally in an English language & that becomes that becomes our thinking process & generally used in our conservation
On native, of course (if I think by words...). Only if I try to speak with English-speaking people, I start think on "pidgin-English", to facilitate the construction of phrases.
A good objects are emigrants. It's funny to talk with them. They not only control the content, but also the form. There is a type of people who acquire a significant accent on native language very quickly. Moreover, they speak the “new” language with an even more terrible accent, or even a mixture of languages (both in Russia and in USA, their language is called Runglish, or Russlish). The formation of such "languages" is not news for emigrants (in Russian, Mayakovsky and Teffi wrote about this). I was always interested in the language in which the migrant’s “thinking process” takes place. Rather, all - no matter what! Thinking often happens outside the language, and the result is already invested in language forms!!! In any case, in the process of thinking, I mentally utter only keywords, and the rest appears "from nowhere" in the form of visual images.
Once an English colleague said me: "You have become better to speak English" - "Why ???" - You began to stutter in English, i.e. you speak automatically, without controlling yourself ... "(in Russian, I stutter very strongly)...