Do people dream in a specific language? I can think in more than one language, but my dreams are abstract, rather than verbal.

I have a bilingual friend who claims after spending few weeks in Australia or Japan his dreams switch to the local vocabulary.

When I was living in Spain I definitely started dreaming in Spanish (it's weird to describe... ) and I know foreign friends of mine have shared similar experiences where they started dreaming in English in the US.

Haven't flipped the switch on my Portuguese yet, but I'm trying..