If you want a real challenge. Try speaking German with Germans when they can tell you are a native English speaker. For a decade or two, you could avoid the switch if you stuck to the Eastern parts of Germany near Poland.

Usually, Germans will only stick with German while I am amusing them. Since I am older, they expect me to sound like a GenX person. The thing is, I learned German using both traditional courses but also a whole lot of YouTube (mostly contemporary Stand-Up Comedy) and Sesamstrasse. So not only do I speak with mannerisms of younger Millenials, I have a whole mix of regional slang mixed in that normally wouldn’t be together.