-when you can translate everything you see from your native language into another language
-instead of taking notes in your native language, you write them in a different language (for example, you write in Japanese when taking English notes)
-you can communicate with your hairdresser in their native language, and they can actually understand you to the point that they don't mess up your haircut.
-when you overhear someone speaking in another language, you can automatically understand them
-you don't need subtitles when you're watching a show in another language
-your thoughts are constantly in another language
-you have a fast reading rate when reading in another language