Help! (categori.php?)

Hi!
I am transelating my website, http://www.golfsiden.net
on the front page everything is fine and in norwegian. But if you go in to an spesific category the language change to english, how do i change that?

“A Category Page
is_category()
When any Category archive page is being displayed.”

I Cat find the category.php file, where it is?
I need to edit category.php to change the language on the category pages, right?

Pleas help me…!