The Essay - Lingua Franca - Lost Your Tongue?

Lingua Franca Michael Rosen continues his exploration of the ways Europeans speak. 9/12. Lost Your Tongue? Punjabi, Sylheti, Vietnamese, Hausa and many others have travelled to Europe with their native speakers, yet immediately find themselves surrounded by English, French, German, Dutch and the rest. So what does it take for a non-native language to survive, flourish or simply die?