In the config word document it says the language file needs to be updated, does this mean the one inside the jar, or is there a way to do this without recompiling everything (pretty new at that sort of thing)

Ok, thanks :)

You can do this through a resource pack.
http://www.minecraftforum.net/forums/mapping-and-modding/resource-packs/resource-pack-discussion/1256295-how-to-make-a-language-changing-names-of-items?comment=4