diff --git a/nova/api/openstack/wsgi.py b/nova/api/openstack/wsgi.py
index 13f6af44525d..406ddf7489c2 100644
--- a/nova/api/openstack/wsgi.py
+++ b/nova/api/openstack/wsgi.py
@@ -1,5 +1,6 @@
 # vim: tabstop=4 shiftwidth=4 softtabstop=4
 
+# Copyright 2013 IBM Corp.
 # Copyright 2011 OpenStack Foundation
 # All Rights Reserved.
 #
@@ -25,6 +26,7 @@ import webob
 
 from nova.api.openstack import xmlutil
 from nova import exception
+from nova.openstack.common import gettextutils
 from nova.openstack.common.gettextutils import _
 from nova.openstack.common import jsonutils
 from nova.openstack.common import log as logging
@@ -176,6 +178,12 @@ class Request(webob.Request):
 
         return content_type
 
+    def best_match_language(self):
+        """Determine language for returned response."""
+        return self.accept_language.best_match(
+                gettextutils.get_available_languages('nova'),
+                default_match='en_US')
+
 
 class ActionDispatcher(object):
     """Maps method name to local methods through action name."""
@@ -925,7 +933,7 @@ class Resource(wsgi.Application):
                     "%(body)s") % {'action': action,
                                    'body': unicode(body, 'utf-8')}
             LOG.debug(msg)
-        LOG.debug(_("Calling method %s") % meth)
+        LOG.debug(_("Calling method %s") % str(meth))
 
         # Now, deserialize the request body...
         try:
@@ -1180,6 +1188,8 @@ class Fault(webob.exc.HTTPException):
     @webob.dec.wsgify(RequestClass=Request)
     def __call__(self, req):
         """Generate a WSGI response based on the exception passed to ctor."""
+
+        user_locale = req.best_match_language()
         # Replace the body with fault details.
         code = self.wrapped_exc.status_int
         fault_name = self._fault_names.get(code, "computeFault")
@@ -1187,6 +1197,8 @@ class Fault(webob.exc.HTTPException):
         LOG.debug(_("Returning %(code)s to user: %(explanation)s"),
                   {'code': code, 'explanation': explanation})
 
+        explanation = gettextutils.get_localized_message(explanation,
+                                                         user_locale)
         fault_data = {
             fault_name: {
                 'code': code,
@@ -1250,9 +1262,19 @@ class RateLimitFault(webob.exc.HTTPException):
         Return the wrapped exception with a serialized body conforming to our
         error format.
         """
+        user_locale = request.best_match_language()
         content_type = request.best_match_content_type()
         metadata = {"attributes": {"overLimit": ["code", "retryAfter"]}}
 
+        self.content['overLimit']['message'] = \
+                gettextutils.get_localized_message(
+                        self.content['overLimit']['message'],
+                        user_locale)
+        self.content['overLimit']['details'] = \
+                gettextutils.get_localized_message(
+                        self.content['overLimit']['details'],
+                        user_locale)
+
         xml_serializer = XMLDictSerializer(metadata, XMLNS_V11)
         serializer = {
             'application/xml': xml_serializer,
diff --git a/nova/cmd/__init__.py b/nova/cmd/__init__.py
index 87edf9b4b957..a0d4dc38d908 100644
--- a/nova/cmd/__init__.py
+++ b/nova/cmd/__init__.py
@@ -32,3 +32,6 @@ os.environ['EVENTLET_NO_GREENDNS'] = 'yes'
 import eventlet
 
 eventlet.monkey_patch(os=False)
+
+from nova.openstack.common import gettextutils
+gettextutils.enable_lazy()
diff --git a/nova/compute/manager.py b/nova/compute/manager.py
index d1be4b45f6ae..126e50796fee 100755
--- a/nova/compute/manager.py
+++ b/nova/compute/manager.py
@@ -911,7 +911,7 @@ class ComputeManager(manager.SchedulerDependentManager):
             info = extra_usage_info.copy()
             if not msg:
                 msg = ""
-            info['message'] = msg
+            info['message'] = unicode(msg)
             self._notify_about_instance_usage(context, instance, type_,
                     extra_usage_info=info, **kwargs)
 
diff --git a/nova/test.py b/nova/test.py
index f7c68e7b9f31..2f98d6374ff8 100644
--- a/nova/test.py
+++ b/nova/test.py
@@ -27,6 +27,7 @@ import eventlet
 eventlet.monkey_patch(os=False)
 
 import copy
+import gettext
 import os
 import shutil
 import sys
@@ -191,6 +192,17 @@ class MoxStubout(fixtures.Fixture):
         self.addCleanup(self.mox.VerifyAll)
 
 
+class TranslationFixture(fixtures.Fixture):
+    """Use gettext NullTranslation objects in tests."""
+
+    def setUp(self):
+        super(TranslationFixture, self).setUp()
+        nulltrans = gettext.NullTranslations()
+        gettext_fixture = fixtures.MonkeyPatch('gettext.translation',
+                                               lambda *x, **y: nulltrans)
+        self.gettext_patcher = self.useFixture(gettext_fixture)
+
+
 class TestingException(Exception):
     pass
 
@@ -216,6 +228,7 @@ class TestCase(testtools.TestCase):
             self.useFixture(fixtures.Timeout(test_timeout, gentle=True))
         self.useFixture(fixtures.NestedTempfile())
         self.useFixture(fixtures.TempHomeDir())
+        self.useFixture(TranslationFixture())
 
         if (os.environ.get('OS_STDOUT_CAPTURE') == 'True' or
                 os.environ.get('OS_STDOUT_CAPTURE') == '1'):
diff --git a/nova/tests/api/openstack/compute/contrib/test_floating_ips.py b/nova/tests/api/openstack/compute/contrib/test_floating_ips.py
index abd25401f9a9..a781c6bf2b5f 100644
--- a/nova/tests/api/openstack/compute/contrib/test_floating_ips.py
+++ b/nova/tests/api/openstack/compute/contrib/test_floating_ips.py
@@ -17,7 +17,6 @@
 import uuid
 
 from lxml import etree
-import testtools
 import webob
 
 from nova.api.openstack.compute.contrib import floating_ips
@@ -306,9 +305,10 @@ class FloatingIpTest(test.TestCase):
         self.stubs.Set(network.api.API, "allocate_floating_ip", fake_allocate)
 
         req = fakes.HTTPRequest.blank('/v2/fake/os-floating-ips')
-        with testtools.ExpectedException(webob.exc.HTTPNotFound,
-                                         'No more floating ips'):
-            self.controller.create(req)
+        ex = self.assertRaises(webob.exc.HTTPNotFound,
+                               self.controller.create, req)
+
+        self.assertIn('No more floating ips', ex.explanation)
 
     def test_floating_ip_allocate_no_free_ips_pool(self):
         def fake_allocate(*args, **kwargs):
@@ -317,10 +317,11 @@ class FloatingIpTest(test.TestCase):
         self.stubs.Set(network.api.API, "allocate_floating_ip", fake_allocate)
 
         req = fakes.HTTPRequest.blank('/v2/fake/os-floating-ips')
-        with testtools.ExpectedException(
-                webob.exc.HTTPNotFound,
-                'No more floating ips in pool non_existant_pool'):
-            self.controller.create(req, {'pool': 'non_existant_pool'})
+        ex = self.assertRaises(webob.exc.HTTPNotFound,
+            self.controller.create, req, {'pool': 'non_existant_pool'})
+
+        self.assertIn('No more floating ips in pool non_existant_pool',
+                      ex.explanation)
 
     def test_floating_ip_allocate(self):
         def fake1(*args, **kwargs):
diff --git a/nova/tests/api/openstack/fakes.py b/nova/tests/api/openstack/fakes.py
index d12d6bfc6cd6..3d789848a3e3 100644
--- a/nova/tests/api/openstack/fakes.py
+++ b/nova/tests/api/openstack/fakes.py
@@ -699,3 +699,8 @@ def stub_snapshot_get_all(self, context):
 def stub_bdm_get_all_by_instance(context, instance_uuid):
     return [{'source_type': 'volume', 'volume_id': 'volume_id1'},
             {'source_type': 'volume', 'volume_id': 'volume_id2'}]
+
+
+def fake_get_available_languages(domain):
+    existing_translations = ['en_GB', 'en_AU', 'de', 'zh_CN', 'en_US']
+    return existing_translations
diff --git a/nova/tests/api/openstack/test_faults.py b/nova/tests/api/openstack/test_faults.py
index 879afde387d7..89ff61a63176 100644
--- a/nova/tests/api/openstack/test_faults.py
+++ b/nova/tests/api/openstack/test_faults.py
@@ -1,5 +1,6 @@
 # vim: tabstop=4 shiftwidth=4 softtabstop=4
 
+# Copyright 2013 IBM Corp.
 # Copyright 2010 OpenStack Foundation
 # All Rights Reserved.
 #
@@ -23,6 +24,7 @@ import webob.exc
 
 from nova.api.openstack import common
 from nova.api.openstack import wsgi
+from nova.openstack.common import gettextutils
 from nova.openstack.common import jsonutils
 from nova import test
 
@@ -138,6 +140,22 @@ class TestFaults(test.TestCase):
         self.assertTrue('resizeNotAllowed' not in resp.body)
         self.assertTrue('forbidden' in resp.body)
 
+    def test_raise_localize_explanation(self):
+        msgid = "String with params: %s"
+        params = ('blah', )
+        lazy_gettext = gettextutils._
+        expl = lazy_gettext(msgid) % params
+
+        @webob.dec.wsgify
+        def raiser(req):
+            raise wsgi.Fault(webob.exc.HTTPNotFound(explanation=expl))
+
+        req = webob.Request.blank('/.xml')
+        resp = req.get_response(raiser)
+        self.assertEqual(resp.content_type, "application/xml")
+        self.assertEqual(resp.status_int, 404)
+        self.assertTrue((msgid % params) in resp.body)
+
     def test_fault_has_status_int(self):
         # Ensure the status_int is set correctly on faults.
         fault = wsgi.Fault(webob.exc.HTTPBadRequest(explanation='what?'))
diff --git a/nova/tests/api/openstack/test_wsgi.py b/nova/tests/api/openstack/test_wsgi.py
index 41a80a65c414..08812e44ee39 100644
--- a/nova/tests/api/openstack/test_wsgi.py
+++ b/nova/tests/api/openstack/test_wsgi.py
@@ -5,6 +5,7 @@ import webob
 
 from nova.api.openstack import wsgi
 from nova import exception
+from nova.openstack.common import gettextutils
 from nova import test
 from nova.tests.api.openstack import fakes
 from nova.tests import utils
@@ -97,6 +98,53 @@ class RequestTest(test.TestCase):
                  'uuid1': instances[1],
                  'uuid2': instances[2]})
 
+    def test_from_request(self):
+        self.stubs.Set(gettextutils, 'get_available_languages',
+                       fakes.fake_get_available_languages)
+
+        request = wsgi.Request.blank('/')
+        accepted = 'bogus;q=1.1, en-gb;q=0.7,en-us,en;q=.5,*;q=.7'
+        request.headers = {'Accept-Language': accepted}
+        self.assertEqual(request.best_match_language(), 'en_US')
+
+    def test_asterisk(self):
+        # asterisk should match first available if there
+        # are not any other available matches
+        self.stubs.Set(gettextutils, 'get_available_languages',
+                       fakes.fake_get_available_languages)
+
+        request = wsgi.Request.blank('/')
+        accepted = '*,es;q=.5'
+        request.headers = {'Accept-Language': accepted}
+        self.assertEqual(request.best_match_language(), 'en_GB')
+
+    def test_prefix(self):
+        self.stubs.Set(gettextutils, 'get_available_languages',
+                       fakes.fake_get_available_languages)
+
+        request = wsgi.Request.blank('/')
+        accepted = 'zh'
+        request.headers = {'Accept-Language': accepted}
+        self.assertEqual(request.best_match_language(), 'zh_CN')
+
+    def test_secondary(self):
+        self.stubs.Set(gettextutils, 'get_available_languages',
+                       fakes.fake_get_available_languages)
+
+        request = wsgi.Request.blank('/')
+        accepted = 'nn,en-gb;q=.5'
+        request.headers = {'Accept-Language': accepted}
+        self.assertEqual(request.best_match_language(), 'en_GB')
+
+    def test_none_found(self):
+        self.stubs.Set(gettextutils, 'get_available_languages',
+                       fakes.fake_get_available_languages)
+
+        request = wsgi.Request.blank('/')
+        accepted = 'nb-no'
+        request.headers = {'Accept-Language': accepted}
+        self.assertEqual(request.best_match_language(), 'en_US')
+
 
 class ActionDispatcherTest(test.TestCase):
     def test_dispatch(self):
diff --git a/nova/tests/api/test_auth.py b/nova/tests/api/test_auth.py
index 6091e19c1cb4..f73bc0c617b8 100644
--- a/nova/tests/api/test_auth.py
+++ b/nova/tests/api/test_auth.py
@@ -78,9 +78,9 @@ class TestKeystoneMiddlewareRoles(test.TestCase):
             context = req.environ['nova.context']
 
             if "knight" in context.roles and "bad" not in context.roles:
-                return webob.Response(status=_("200 Role Match"))
+                return webob.Response(status="200 Role Match")
             elif context.roles == ['']:
-                return webob.Response(status=_("200 No Roles"))
+                return webob.Response(status="200 No Roles")
             else:
                 raise webob.exc.HTTPBadRequest(_("unexpected role header"))
 
diff --git a/nova/utils.py b/nova/utils.py
index 2bfa9495f73a..79aa19ae362e 100644
--- a/nova/utils.py
+++ b/nova/utils.py
@@ -43,6 +43,7 @@ from oslo.config import cfg
 
 from nova import exception
 from nova.openstack.common import excutils
+from nova.openstack.common import gettextutils
 from nova.openstack.common.gettextutils import _
 from nova.openstack.common import importutils
 from nova.openstack.common import lockutils
@@ -476,6 +477,8 @@ def utf8(value):
     """
     if isinstance(value, unicode):
         return value.encode('utf-8')
+    elif isinstance(value, gettextutils.Message):
+        return unicode(value).encode('utf-8')
     assert isinstance(value, str)
     return value
 
diff --git a/nova/virt/driver.py b/nova/virt/driver.py
index c69224c4c102..3ba3b802d77b 100755
--- a/nova/virt/driver.py
+++ b/nova/virt/driver.py
@@ -1004,7 +1004,7 @@ class ComputeDriver(object):
         """
 
         if not self._compute_event_callback:
-            LOG.debug(_("Discarding event %s") % event)
+            LOG.debug(_("Discarding event %s") % str(event))
             return
 
         if not isinstance(event, virtevent.Event):
@@ -1012,7 +1012,7 @@ class ComputeDriver(object):
                 _("Event must be an instance of nova.virt.event.Event"))
 
         try:
-            LOG.debug(_("Emitting event %s") % event)
+            LOG.debug(_("Emitting event %s") % str(event))
             self._compute_event_callback(event)
         except Exception as ex:
             LOG.error(_("Exception dispatching event %(event)s: %(ex)s"),
diff --git a/nova/virt/libvirt/driver.py b/nova/virt/libvirt/driver.py
index 78643cee674b..255d5064831c 100755
--- a/nova/virt/libvirt/driver.py
+++ b/nova/virt/libvirt/driver.py
@@ -583,7 +583,8 @@ class LibvirtDriver(driver.ComputeDriver):
                 self._wrapped_conn = wrapped_conn
 
             try:
-                LOG.debug(_("Registering for lifecycle events %s") % self)
+                LOG.debug(_("Registering for lifecycle events %s") %
+                          str(self))
                 wrapped_conn.domainEventRegisterAny(
                     None,
                     libvirt.VIR_DOMAIN_EVENT_ID_LIFECYCLE,
@@ -595,8 +596,8 @@ class LibvirtDriver(driver.ComputeDriver):
 
             if self.has_min_version(MIN_LIBVIRT_CLOSE_CALLBACK_VERSION):
                 try:
-                    LOG.debug(_("Registering for connection events: %s")
-                                % self)
+                    LOG.debug(_("Registering for connection events: %s") %
+                              str(self))
                     wrapped_conn.registerCloseCallback(
                         self._close_callback, None)
                 except libvirt.libvirtError: