new file mode 100644
--- /dev/null
+++ b/babel/messages/checkers.py
@@ -0,0 +1,48 @@
+# -*- coding: utf-8 -*-
+#
+# Copyright (C) 2007 Edgewall Software
+# All rights reserved.
+#
+# This software is licensed as described in the file COPYING, which
+# you should have received as part of this distribution. The terms
+# are also available at http://babel.edgewall.org/wiki/License.
+#
+# This software consists of voluntary contributions made by many
+# individuals. For the exact contribution history, see the revision
+# history and logs, available at http://babel.edgewall.org/log/.
+
+"""Various routines that help with validation of translations."""
+
+from babel.messages.catalog import TranslationError, PYTHON_FORMAT
+
+def num_plurals(catalog, message):
+    """Verify the number of plurals in the translation."""
+    if not message.pluralizable:
+        if not isinstance(message.string, basestring):
+            raise TranslationError("Found plural forms for non-pluralizable "
+                                   "message")
+        return
+
+    msgstrs = message.string
+    if not isinstance(msgstrs, (list, tuple)):
+        msgstrs = (msgstrs,)
+    if len(msgstrs) != catalog.num_plurals:
+        raise TranslationError("Wrong number of plural forms (expected %d)" %
+                               catalog.num_plurals)
+
+def python_format(catalog, message):
+    if 'python-format' in message.flags:
+        msgids = message.id
+        if not isinstance(msgids, (list, tuple)):
+            msgids = (msgids,)
+        msgstrs = message.string
+        if not isinstance(msgstrs, (list, tuple)):
+            msgstrs = (msgstrs,)
+        for idx, msgid in enumerate(msgids):
+            if not msgstrs[idx]:
+                continue # no translation
+            for match in PYTHON_FORMAT.finditer(msgid):
+                param = match.group(0)
+                if param not in msgstrs[idx]:
+                    raise TranslationError("Python parameter %s not found in "
+                                           "translation" % param)