And two more things...
Do you have the latest version of Wedge,
What is your browser's default language?
@Nao From http://wedge.org/pub/feats/8542/poll-default-language/
"User's choice, then your browser's language (if available in the installed language list), then the site's default language"
The issue appears to be that when "Enable user-selectable language support" is off then Wedge is using the browser's language even when that language is not marked as 'Available'.
(Why are some topics in 'Archived fixes' when they're not marked as solved....?)