A word by word replacement would be great. For example in an RPG, begin in all English but as you go on begin to slowly replace common words (with explanations

A word by word replacement would be great. For example in an RPG, begin in all English but as you go on begin to slowly replace common words (with explanations as necessary); then later begin to fix grammar and sentence structure. I recently read Shogun and it's pretty interesting how you pick up a few bits of the language here and there.