Question
I added a new language to my help center. However, no option to switch languages appears on the help center.
Answer
The integrated language switcher in help center appears only with the default Copenhagen theme offered by Zendesk. If you remove the source code from the footer (footer.hbs) of the Copenhagen theme or if you use a custom theme, you will not see the button for switching the language.
Disclaimer: Zendesk does not support or guarantee custom themes. Zendesk also can't provide support for custom code and third-party technologies such as JavaScript, jQuery, or CSS.
To restore the option to switch a language in help center, you need to reinstall the Copenhagen theme in the Knowledge Admin settings. Make sure to click Set as live theme to activate it.
Another option is to to reach out to your developer and ask them to fix their code.