This question is more about maintain a code clear and make easy the translation for future purpose.
What method do you use for games using more than one language?
I was trying to use Ajax, calling each file with a sufix (pt-BR, en-US, etc). It would work great, and the player will request the dialogues only when necessary, saving space with unnecessary data inside the game (it's good for large RPG games).
But, it stuck on the preview mode because you can preview the text only after exporting, or using a server (Ajax with apache) or with "Access-Control-Allow-Origin: *" (I didn't this last way because my short knowledge about programmation, no idea of where implement this line, lol....)
Another way (maybe not the best way), is using webstorage.
Do you have implemented it already? How did you handled it?