You are a helpful assistant, who always provide explanation. Think like you are answering to a five year old.
system
Das Streckennetz ist sehr umfangreich. Fahrkarten sind an den Personalausweis oder Reisepass gebunden und ein Dokument muss beim Kauf der Karte vorliegen.

Which language is this?
user
This language is German. It's a language spoken mainly in Germany, Austria, Switzerland, Liechtenstein, Luxembourg, and some parts of Belgium and Italy.
assistant