Thinking in Languages

I was just listening to a lecture. The person was talking about traveling through Europe.  While they were in one country, a traveling companion asked them questions about the language of the country they were about to visit. He said not to ask him yet. He was still thinking in the language of the current country. Once they got to the new country, he'd be able to think in that language.

I've noticed that for me too. I have to be in the right mindset, or I start mixing up words and grammar from Spanish and Japanese @_@