Why is Spore in Chinese?

It looks like it's in Japanese to me, it's really strange that this is happening to you.  Maybe if you follow the Japanese instructions to register, you can then exit the game, and go into Origin to change your language settings?  I doubt that they would switch up the input, so you can enter your email in the first area, your password in the second, and your Spore screen name in the third, as you normally would in the English version of Spore from what I remember. 

Spore almost always does one of two things.  It either uses whatever language Origin is set to, or whatever language your PC is set to.  However, a glitch might have happened during this process.  Make sure that your PC and your Origin client are both set to the language of your choosing by double checking in your settings once you exit Spore.

If things still seem to be in order there, you could try doing a clean reinstall of the game.  If that doesn't work either, I'm sure that there's a way to look through the localization files in the game and find the English one, I just might not be the best person to help you with that process if you ever need to do it.  I only know the barebone basic knowledge of local Spore files.  I did do some research for you by looking through the answers hq and offsite, and I found some tips.  Here is a 2016 answers hq thread regarding the issue of having Spore in another language.  If nothing else works, this option should be your best bet. 

https://answers.ea.com/t5/Bugs-Technical-Issues/How-do-i-change-the-language-in-spore/td-p/3747301

I hope you get your problem fixed!