Stand-up comedian Henning Wehn takes over a German class and highlights the importance of the four additional German letters in the alphabet, the ß, ä, ü and ö. Where would Düsseldorf be ...

10 revealing facts about German. Get your head around tongue twisters and jokes. It's also available in German with audio.

Germany is to revamp its phonetic alphabet to remove words added by the ... for the problematic letters is now in the hands of the German Institute for Standardization (DIN).