...It's not allowed to make a mod with assets from one game for the other and share it with the rest of the world, something the typical modder does.
sometimes it might even be too much to publish a simple text file.
I remember more than a decade ago when Civilization 3 came out...
in germany it was published first in the english version, with no german language options whatsoever...
every text from the game menus and dialogues was stored in simple textfiles.
As Infogrames (now Atari) germany already had announced that a german version of Civ 3 woulodn´t be available in the stores for more than half a year, Coldfever, a well known modder thought it would be a good idea to translate said textfiles and offer them on his homepage for free.
Well, he announced the project in the official Infogrames Forum and even wrote a mail to Infogrames, informning them about this project and offering his services for the translation of Civ 3 into to official german version
and finally (after getting no replky from Infogrames and completing the translation) he offered said textfiles for download on his homepage.
This was a bad idea however, as shortly thereafter he got mail from the lawyers of Infogrames,
containing a cease and desist order which he ways forced to sign (in which he had to state that he, under contractual penalty, would never ever offer modified Civ 3 files anymore)
See here for a short version:
(almost all other sources for this case are in german)
(Fortunately SiCh and Taleworlds aren´t Infogrames, so I assume that they would handle such a case wthout lawyers first