Hi Sidonia,
You can not directly translate the English categories into another language as such using Little Reader.
Rather you need to manually create new word files yourself and then input the 'word' yourself, the 'word' can be Japanese, French, German or whatever language you like, depending on what language packs you have installed on your computer.
This is explained in more detail at the top of this board
Also, if you have not done already please check out our foreign download categories by going to the 'Forum' tab then scrolling on the 'Little Reader Library' tab and then clicking 'Foreign Language Lesson Downloads'.
Hope this helps!