diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,8 @@
+## 1.4.26
+
+* Modify `languages` so that, if you previously called `setLanguage`, the newly
+  set language will be reflected.
+
 ## 1.4.25
 
 * Add instance of MonadHandler and MonadWidget for ExceptT [#1278](https://github.com/yesodweb/yesod/pull/1278)
diff --git a/Yesod/Core/Handler.hs b/Yesod/Core/Handler.hs
--- a/Yesod/Core/Handler.hs
+++ b/Yesod/Core/Handler.hs
@@ -1053,7 +1053,10 @@
 --
 -- This is handled by parseWaiRequest (not exposed).
 languages :: MonadHandler m => m [Text]
-languages = reqLangs <$> getRequest
+languages = do
+    mlang <- lookupSession langKey
+    langs <- reqLangs <$> getRequest
+    return $ maybe id (:) mlang langs
 
 lookup' :: Eq a => a -> [(a, b)] -> [b]
 lookup' a = map snd . filter (\x -> a == fst x)
diff --git a/yesod-core.cabal b/yesod-core.cabal
--- a/yesod-core.cabal
+++ b/yesod-core.cabal
@@ -1,5 +1,5 @@
 name:            yesod-core
-version:         1.4.25
+version:         1.4.26
 license:         MIT
 license-file:    LICENSE
 author:          Michael Snoyman <michael@snoyman.com>