diff --git a/django/utils/translation/trans_real.py b/django/utils/translation/trans_real.py
index cce2a8cb864..9e94840ee0b 100644
--- a/django/utils/translation/trans_real.py
+++ b/django/utils/translation/trans_real.py
@@ -30,9 +30,10 @@ _accepted = {}
 # magic gettext number to separate context from message
 CONTEXT_SEPARATOR = "\x04"
 
-# Format of Accept-Language header values. From RFC 2616, section 14.4 and 3.9.
+# Format of Accept-Language header values. From RFC 2616, section 14.4 and 3.9
+# and RFC 3066, section 2.1
 accept_language_re = re.compile(r'''
-        ([A-Za-z]{1,8}(?:-[A-Za-z]{1,8})*|\*)         # "en", "en-au", "x-y-z", "*"
+        ([A-Za-z]{1,8}(?:-[A-Za-z0-9]{1,8})*|\*)      # "en", "en-au", "x-y-z", "es-419", "*"
         (?:\s*;\s*q=(0(?:\.\d{,3})?|1(?:.0{,3})?))?   # Optional "q=1.00", "q=0.8"
         (?:\s*,\s*|$)                                 # Multiple accepts per header.
         ''', re.VERBOSE)
diff --git a/tests/regressiontests/i18n/tests.py b/tests/regressiontests/i18n/tests.py
index bce3d617d23..45471a9678c 100644
--- a/tests/regressiontests/i18n/tests.py
+++ b/tests/regressiontests/i18n/tests.py
@@ -715,6 +715,7 @@ class MiscTests(TestCase):
         # Good headers.
         self.assertEqual([('de', 1.0)], p('de'))
         self.assertEqual([('en-AU', 1.0)], p('en-AU'))
+        self.assertEqual([('es-419', 1.0)], p('es-419'))
         self.assertEqual([('*', 1.0)], p('*;q=1.00'))
         self.assertEqual([('en-AU', 0.123)], p('en-AU;q=0.123'))
         self.assertEqual([('en-au', 0.5)], p('en-au;q=0.5'))
@@ -739,6 +740,7 @@ class MiscTests(TestCase):
         self.assertEqual([], p('da, en-gb;q=0.8, en;q=0.7,#'))
         self.assertEqual([], p('de;q=2.0'))
         self.assertEqual([], p('de;q=0.a'))
+        self.assertEqual([], p('12-345'))
         self.assertEqual([], p(''))
 
     def test_parse_literal_http_header(self):