Don’t worry - it’s not intended for the NA client to work like this. There are historically differences with the Chinese client - this much is true, but you aren’t playing on the Chinese client. You’re playing on the North American client. The Classic client is just a modified version of the client that we use for Battle for Azeroth right now, so it should allow use of Simplified Chinese when it’s not bugged.
This is simply a bug, and we’re working on it. There was a similar bug a month or so ago with the live client, but the two clients were being developed separately so the fix for this didn’t make it into the Classic client. I’m sorry we don’t have an ETA on a fix yet, but this first week we’ve been working on a lot of different issues. If I hear anything else I will definitely let you all know.
There’s no reason for the two of you to argue over this - let’s keep this focused on the tech support/bug aspect please. ^^