Hi there!
There aren't any such limitations as long as your submission falls within the jam's theme (books, comics or poetry) - the only exception I can think of is if someone were to write one word then submit it, we probably can't process this.
Yes you may submit translations, too, thougb be aware this won't change the amount of royalties received as they are per creator not per project.
Thank you so much for your interest in our bundle, wishing you an awesome day!