In Berlin, a city whose inhabitants come from 184 countries, I hear many different languages every day: from the Arabic-speaking kids I see in the mornings on their way to school to the Italian waiters chit-chatting under my window just before I fall asleep at night. I speak Swedish , English and German , so for the most part, these other languages feel more like background noise, or ambient music in a bar.

Until, that is, a word or phrase I recognize suddenly pops into an otherwise random stream of sounds. A mother scolding her child in Turkish suddenly says, in German, Und das kannst du einfach nicht machen, verstehst du? (“You simply can’t do that, understand?”). On the subway, a couple of Finnish twentysomethings insert an “I gotta make up my mind!” into their Finnish conversation. A Swabian colleague calls her mom, and suddenly speaks in a language that definitely isn’t the German I learned when I moved here from Sweden.

What do these people all have in common?…