Validate requested language against known language codes. (#552)
Validate requested language against known language codes. (#552)

In case someone asks for something we don't recognize, fall back to the
default language for the repository.
google/personfinder,gimite/personfinder,gimite/personfinder,google/personfinder,gimite/personfinder,google/personfinder,gimite/personfinder,google/personfinder