The Chat widget is set to automatic language detection, but it always shows just the text that was entered in the Widget configuration. Even when I try with Accept-Language headers as defined here: https://support.zendesk.com/hc/en-us/articles/203761906 like 'fr', for example.
I can use the zopim API to force it to different language, but even then the text on the minimized chat window is still not translated!
To be honest, for an expensive Enterprise account, the functionality and documentation of the Chat widget is just plain horrible and headache-inducing.