Hello -
You've posted this here a few times now, and I think it's a
really great idea for a game. There's not really anything available that's fun and really game-like for learning languages, especially Chinese (besides very basic games aimed at very small children).
However... the game, as it is, is ... totally boring, and not a useful teaching aid. Ni Hao-ing at a heap of NPCs is just neither fun, nor educational.

I think you need to do a bit of research on language teaching, and apply those techniques to a game design. See if you can come up with a battle-system that uses similar techniques to duo-lingo for example. And incorporate audio if you're teaching spoken Mandarin vs written Chinese.
I think you need to address this sort of thing before worrying about graphics, but I hope you continue the project, as it certainly could be great.