Rails I18n : Internationalization for Ruby on Rails

I18n available_locales

This might work in some scenarios to retrieve the available translations from the Simple backend:

module I18n
  class << self
    def available_locales
      backend.available_locales
    end
  end

  module Backend
    class Simple
      def available_locales
        translations.keys
      end
    end
  end
end