You must not work on any mod without a clear permission, that goes without saying.
Actually, it's far better to clearly state whether your mod is open to outside development or not--it helps if a mod ever "dies". Note that in The Order's case, it's pretty clear on the first post, and the fact that it is still in active development, that anyone who wants to help should ask first. However, some other mods are far less clear, and it's better not to take such things for granted.
Also, and I'm not quite sure if this is an ESL thing, but your posts came off quite rude, and you are
not normally like that Xerxes...
Still eagerly awaiting the translation, whenever it comes :foodndrink: