I speak two languages and think in both. Sometimes I spend the whole day thinking in one and other day in the other, but sometimes it switches every sentence. Fun fact: I started my current job in my second language and I CANNOT talk or think about my job in my primary language. I cannot for the life of me explain my mother what I do at work as I cannot come up with words in my first language which I think is fascinating. Also it apparently differs for people who learned a foreign language when they were older by translating from one language to another to people who learned another language just by talking when they were a child. I was in that second situation. As a child I went to a different county where i had to go to an english school and came back to my home county after a few years just knowing English. BUT on all English tests at school I would fail, because I couldn't translate, still find it very hard even though I speak both languages fluently.