diff --git a/openerp/http.py b/openerp/http.py
index eddbcb669a396b1efb8676444d4f6fd2b9de6f13..f25d77fa3a78ce906c1a0721c1b912182ebe0336 100644
--- a/openerp/http.py
+++ b/openerp/http.py
@@ -207,6 +207,7 @@ class WebRequest(object):
 
     @lazy_property
     def lang(self):
+        self.session._fix_lang(self.context)
         return self.context["lang"]
 
     @lazy_property
@@ -957,7 +958,7 @@ class OpenERPSession(werkzeug.contrib.sessions.Session):
 
         :param dict context: context to fix
         """
-        lang = context['lang']
+        lang = context.get('lang')
 
         # inane OpenERP locale
         if lang == 'ar_AR':