If its an actual item, such as weapon, armor, book, or anything that the player can actually see/use in game, you can do it using the Creation Kit, a tool to help you with Skyrim modding.
I've downloaded and activated the Creation Kit, but wenn I try to load the (German) main skyrim file
there are dozens of error messages. The reason why I try to translate (back) things in Skyrim is that
I installed the unofficial Patches (to get rid off several bugs) and now there's a mix of German and
English strings (and even sound files) in the game - which is taxing somehow.
My intention was to translate the unofficial patches themselves but there were even more error
messages coming up when I tried so.