Some websites serve different content to users in different regions, based on the accept-language header used in the header request. So a French visitor who tries to go to the /de/ URL might be redirected to the /fr/ version.
Since this can affect the ability of a website crawler to perform a complete site crawl, Sitebulb allows you to set up URL patterns to correspond with different language options.
To get to Advanced Settings, you scroll to the bottom of the main Audit setup page and hit the grey Advanced Settings button.
The Languages section is under HTTP -> Languages:
To add new language patterns, hit the green button Add New Language, which will bring up an overlay for you to enter the pattern.