- While this is one of the two forms permitted by the Duden, the non-official form tschüß is by far the most common.
- Tschüss was originally common only in northern Germany, but it has gained wider acceptance and is now also commonly used in southern Germany, Austria, Switzerland, and Trentino-Alto Adige in Italy. The farewell auf Wiedersehen is often considered more appropriate to use towards strangers and generally in formal situations in Southern Germany. In Northern and Eastern Germany tschüß it is a standard goodbye in all but official situations.
- tschüs in Duden online