Um, It's Occupied?
You can usually communicate effectively when you have a firm grasp of a language. For example, if you're fluent in English, you should have no trouble navigating situations where everyone speaks English.
However, even with full language proficiency, you might occasionally find yourself at a loss for words. Consider this scenario: what's the best response when someone does this? On second thought, why are you knocking if the public bathroom door is locked?
