diff --git a/user/edit_form.php b/user/edit_form.php
index b18528d2e03..e35b173ccfe 100644
--- a/user/edit_form.php
+++ b/user/edit_form.php
@@ -46,7 +46,14 @@ class user_edit_form extends moodleform {
         // if language does not exist, use site default lang
         if ($langsel = $mform->getElementValue('lang')) {
             $lang = reset($langsel);
-            if (!file_exists($CFG->dataroot.'/lang/'.$lang) and 
+            // missing _utf8 in language, add it before further processing. MDL-11829 MDL-16845
+            if (strpos($lang, '_utf8') === false) {
+                $lang = $lang . '_utf8';
+                $lang_el =& $mform->getElement('lang');
+                $lang_el->setValue($lang);
+            }
+            // check lang exists
+            if (!file_exists($CFG->dataroot.'/lang/'.$lang) and
               !file_exists($CFG->dirroot .'/lang/'.$lang)) {
                 $lang_el =& $mform->getElement('lang');
                 $lang_el->setValue($CFG->lang);
diff --git a/user/editadvanced_form.php b/user/editadvanced_form.php
index 2d16192f537..9ba149862e0 100644
--- a/user/editadvanced_form.php
+++ b/user/editadvanced_form.php
@@ -61,7 +61,14 @@ class user_editadvanced_form extends moodleform {
         // if language does not exist, use site default lang
         if ($langsel = $mform->getElementValue('lang')) {
             $lang = reset($langsel);
-            if (!file_exists($CFG->dataroot.'/lang/'.$lang) and 
+            // missing _utf8 in language, add it before further processing. MDL-11829 MDL-16845
+            if (strpos($lang, '_utf8') === false) {
+                $lang = $lang . '_utf8';
+                $lang_el =& $mform->getElement('lang');
+                $lang_el->setValue($lang);
+            }
+            // check lang exists
+            if (!file_exists($CFG->dataroot.'/lang/'.$lang) and
               !file_exists($CFG->dirroot .'/lang/'.$lang)) {
                 $lang_el =& $mform->getElement('lang');
                 $lang_el->setValue($CFG->lang);