github
"zh-hans" (Chinese (Simplified)) and "zh-hant" (Chinese (Traditional)) translations don't work on a Etherpad Lite server.
This is because Etherpad Lite recognizes these languages as "zh" (Chinese) and because "zh.json" doesn't exist.
Best report this problem with the Etherpad Lite guys.
Thanks. I've started a new issue on GitHub[1]. But it's hard to explain.