The interface and navigation of the GCwiki can be displayed in either official language. This is separate from the content or articles provided by GCwiki members. The responsibility for bilingual content is with the content owners. See How do I make my content billingual?
All members of the GCwiki are able to use the official language of their choice when creating, and editing articles, searching and navigating within GCwiki.
To change your language preferences:
Go to the Preferences tab at the top of the page.
Select your preferred language from the Language drop-down box that is located below the Internationalisation heading.
Scroll to the bottom of the page and click Save.
On the main page of GCwiki, click the language tab that is in the top right corner.
A pop-up window will appear. You may choose your preferred language here.