Chinese keyboard disappeared with macOS High Sierra update

I have seen a few reports of people losing input sources as you describe. It indicates something has gone wrong with your update ( and not that Apple has removed this feature). Try setting up a new user account and see if all is well there.

Safe boot and you can add it back again.

This is killing me, too.

If you create another account, it's still there, but I want it back in my old account.