I used to be fluent in German. I haven't used my German skills more than a handful of times since I finished college in 2010. However, after only three days in Berlin, I find myself having to translate my thoughts to English in order to talk to the Mrs.
I definitely don't have the slang/vernacular down, but I think that I can pass as a someone for whom German is a well studied tongue. I guess it is all coming back. I will be curious to see if I have an accent when I get back to the States mid-September.