Open up the file named localization-frFR.lua inside the folder locales. You will need a decent text editor for this (try using Scite, or Notepad+, find them using a search engine).
Then scroll down to line: 106 and you will currently see this:
["Snowfall Graveyard"] = "Cimeti?re des neiges",
Change it to read:
["Snowfall Graveyard"] = "Cim neige",
Do this same type thing for any other string you want to change and realize if you update you will need to do this again (or somehow not update the addon if you use an autoupdater look for an ignore option)
Edit: looks like the forums aren't UTF-8 capable . . . just pretend there are accented characters in the above codes.