diff --git a/django/utils/cache.py b/django/utils/cache.py
index 9828556057..6cfd893668 100644
--- a/django/utils/cache.py
+++ b/django/utils/cache.py
@@ -25,7 +25,7 @@ from django.core.cache import cache
 from django.utils.encoding import smart_str, iri_to_uri
 from django.utils.http import http_date
 from django.utils.hashcompat import md5_constructor
-from django.utils import translation
+from django.utils.translation import get_language
 from django.http import HttpRequest
 
 cc_delim_re = re.compile(r'\s*,\s*')
@@ -134,6 +134,15 @@ def patch_vary_headers(response, newheaders):
                           if newheader.lower() not in existing_headers]
     response['Vary'] = ', '.join(vary_headers + additional_headers)
 
+def _i18n_cache_key_suffix(request, cache_key):
+    """If enabled, returns the cache key ending with a locale."""
+    if settings.USE_I18N:
+        # first check if LocaleMiddleware or another middleware added
+        # LANGUAGE_CODE to request, then fall back to the active language
+        # which in turn can also fall back to settings.LANGUAGE_CODE
+        cache_key += '.%s' % getattr(request, 'LANGUAGE_CODE', get_language())
+    return cache_key
+
 def _generate_cache_key(request, headerlist, key_prefix):
     """Returns a cache key from the headers given in the header list."""
     ctx = md5_constructor()
@@ -144,18 +153,14 @@ def _generate_cache_key(request, headerlist, key_prefix):
     path = md5_constructor(iri_to_uri(request.path))
     cache_key = 'views.decorators.cache.cache_page.%s.%s.%s' % (
         key_prefix, path.hexdigest(), ctx.hexdigest())
-    if settings.USE_I18N:
-        cache_key += '.%s' % translation.get_language()
-    return cache_key
+    return _i18n_cache_key_suffix(request, cache_key)
 
 def _generate_cache_header_key(key_prefix, request):
     """Returns a cache key for the header cache."""
     path = md5_constructor(iri_to_uri(request.path))
     cache_key = 'views.decorators.cache.cache_header.%s.%s' % (
         key_prefix, path.hexdigest())
-    if settings.USE_I18N:
-        cache_key += ".%s" % translation.get_language()
-    return cache_key
+    return _i18n_cache_key_suffix(request, cache_key)
 
 def get_cache_key(request, key_prefix=None):
     """
diff --git a/docs/topics/cache.txt b/docs/topics/cache.txt
index dc450ae1fc..6c8f1346bb 100644
--- a/docs/topics/cache.txt
+++ b/docs/topics/cache.txt
@@ -323,10 +323,13 @@ more on these decorators.
 .. versionadded:: 1.2
 
 If :setting:`USE_I18N` is set to ``True`` then the generated cache key will
-include the name of the currently active :term:`language<language code>`.
+include the name of the active :term:`language<language code>`.
 This allows you to easily cache multilingual sites without having to create
 the cache key yourself.
 
+See :ref:`topics-i18n-deployment` for more on how Django discovers the active
+language.
+
 __ `Controlling cache: Using other headers`_
 
 The per-view cache
diff --git a/tests/regressiontests/cache/tests.py b/tests/regressiontests/cache/tests.py
index 83422b3a97..9ed93e8750 100644
--- a/tests/regressiontests/cache/tests.py
+++ b/tests/regressiontests/cache/tests.py
@@ -476,7 +476,6 @@ class CacheI18nTest(unittest.TestCase):
                 ('es', 'Spanish'),
         )
         settings.CACHE_MIDDLEWARE_KEY_PREFIX = 'settingsprefix'
-        settings.CACHE_MIDDLEWARE_SECONDS
         self.path = '/cache/test/'
 
     def tearDown(self):