Thanks for reaching out to Apple Support Communities binbincarithers,
We understand you are wanting to use Chinese as one of the keyboards you added and we'd be happy to help assist. To clarify, does Chinese show as one of your available keyboards to switch to when following the steps in the "Switch to another keyboard" section of the article below?
Add or change keyboards on iPhone
Also, would you prefer to switch your system language to Chinese, or would you like to just have it as an available keyboard? Even though you are in the United States, you are still able to switch your system language from English if you'd like.
Change the language on your iPhone, iPad, or iPod touch
Let us know if this helps!