# File lib/extlib/inflection.rb, line 305
      def plural(word)
        # special exceptions
        return "" if word == ""
        if result = plural_of[word]
          return result.dup
        end
        result = word.dup
        regex, hash = pluralization_rules
        result.sub!(regex) {|m| hash[m]}
        plural_of[word] = result
        return result
      end