Index: trunk/virtaal/source_tree_infrastructure/optparse.py
===================================================================
--- trunk.orig/virtaal/source_tree_infrastructure/optparse.py
+++ trunk/virtaal/source_tree_infrastructure/optparse.py
@@ -81,11 +81,16 @@ def _repr(self):
 #   Id: errors.py 509 2006-04-20 00:58:24Z gward
 
 try:
-    from gettext import gettext
+    from gettext import gettext, ngettext
 except ImportError:
     def gettext(message):
         return message
+    def ngettext(singular, plural, n):
+        if n == 1:
+            return singular
+        return plural
 _ = gettext
+n_ = ngettext
 
 
 class OptParseError (Exception):
@@ -1480,11 +1485,7 @@ class OptionParser (OptionContainer):
         if option.takes_value():
             nargs = option.nargs
             if len(rargs) < nargs:
-                if nargs == 1:
-                    self.error(_("%s option requires an argument") % opt)
-                else:
-                    self.error(_("%s option requires %d arguments")
-                               % (opt, nargs))
+                self.error(n_("%s option requires %d arguments") % % (opt, nargs))
             elif nargs == 1:
                 value = rargs.pop(0)
             else: