Ohh, this is a fun thread
Handling just German and English is fine, although I tend to associate writing and reading with English more than with German (thanks be to the internets
).
Adding one other language is okay. Like Japanese. No problem switching back and forth between those intentionally.
But if there is some background noise in yet another language I understand, like Chinese, my brain simply goes *ka-poof!* and I'll either end up jumbling everything together or going completely mute.
On one occasion I did a group project in Japanese with a Taiwanese girl and our Japanese tandem partner helped us out.
The tandem partner has a Canadian boyfriend so our common languages were garbled Japanese and correct English, but she also learned German and Chinese, and would keep throwing those in our respective directions and naturally I had to start answering as well when I understood the Chinese. Then, in some fit of humor our tandem partner decided it would be fun to teach the Taiwanese girl some French...
It lasted for about five minutes and afterwards we had to scrape our brains back together.
It's really difficult to handle that many different languages when they are all spoken by the same people, in the same surroundings, no less.
Something that always happened to me during Japanese oral exams was that I wanted to switch to Spanish (I always found Spanish has a lot of vowels) and to French in Chinese oral exams. French has some really similar sounds like en, un, an and so on.
And of course, as bad as I am in both of those languages, I'm still better in them than in Japanese and Chinese!
Ohhh. And whenever I swear, I unconsciously switch to English, mainly because there is enough swearing in written form on the internet and in books, but also because I was depressed when I did a two year exchange in GB. So, unfortunately, strong negative emotions have become a major connotation for me. *shrugs*