The administrator of your account can change the language of the ZOA interface. The language is set for all users associated with an account. In order to change the language, go to the "Company account" page through the navigation menu on the left hand side.
You can select the account language from the dropdown menu and confirm by clicking on "Save".
ZOA is currently available in four languages:
The interface language can be a different one than the language of the templates for the various categories (e.g. processing activities). Your company account might have English as standard interface language for all users but you might want to document some objects in a different, local language.