Chinese-bought Samsung Galaxy S2 has a very limited language list
You would have to change to another (Android) ROM that has other languages. Take a look at How to Install Stock ROM on Samsung Galaxy S3 (S III GT-I9300).

You can download Nordic firmware at SamFirmware. (Nordic firmware's not in the related links in the link above, but you can follow the first link for the steps in installing/flashing a new ROM)