No, because we are talking about the foreign person trying to learn the new (second) language by total immersion. They obviously aren't going to start thinking in the second language until after they've learned it.

You can start thinking in the second language before you have fully mastered it.

Sure but what happens if you try to think of a word you haven’t learned yet?

Circumlocution. In this case, circumcogitation.

Desh walowda we fo du owbit owta we. (there's more than one way to transfer orbits)