Even though I'm a Portuguese native speaker, sometimes I think and dream in English 

I only have dreamed in english (my native language is spanish), but there were written words in my drea. (I didn't speak). It seems that is very strange to dream in a non native language.

In 3 years ago I dreamt in inglish when study it. but I understand lfew words  that I said in my dreams.lolol

Recently I dreamthat I speak spanish , crazy it.

Part of what got me to take up Spanish again was that even though I hadn't spoken Spanish in 30 years I still sometimes dreamed in Spanish! I sometimes wouldn't even understand everything just like you said Ayr. I figured that some part of me still wanted to speak the language. :D

 Sometimes i dream in english, but i wake up without understand what i was speak in the dream. And i always dream in portuguese (my native language)