How to limit translate amd language module output

I’m a partner of Navision, we do some language translation on navision4.0 for our country, my boss want me to limit user export language package,but I only can use tools/permission to limit translation, that means user can’t use translation menu. at the same time, I found user can use language module to import or outport menu, unless blank Object read & modify right, but my boss need the others can use object designer. he just want keep our language not output, how could I do? thanks,