Tja means something like "Oh well". It's used in Dutch and Swedish.
Tja, die lul heeft ook een paar beuken nodig.
by JeFFJuH April 04, 2005
I don't know about the German, but in the Swedish language it is another way to say hi, used by people that know eachother, and mostly used in the teens
Tja, hur mår du? Translation...Hi, how are you
by Inga from Sweden August 24, 2006