diff --git a/core/modules/language/language.module b/core/modules/language/language.module
index 3fb39e0..e4a5b2e 100644
--- a/core/modules/language/language.module
+++ b/core/modules/language/language.module
@@ -202,6 +202,8 @@ function language_save($language) {
   // Kill the static cache in language_list().
   drupal_static_reset('language_list');
 
+  language_negotiation_url_prefixes_update();
+
   return $language;
 }
 
@@ -403,11 +405,6 @@ function language_language_insert($language) {
 
   language_negotiation_include();
 
-  // Add new language to the list of language prefixes.
-  $prefixes = language_negotiation_url_prefixes();
-  $prefixes[$language->langcode] = (empty($language->default) ? $language->langcode : '');
-  language_negotiation_url_prefixes_save($prefixes);
-
   // Add language to the list of language domains.
   $domains = language_negotiation_url_domains();
   $domains[$language->langcode] = '';
@@ -421,20 +418,6 @@ function language_language_update($language) {
   if (!empty($language->locked)) {
     return;
   }
-
-  language_negotiation_include();
-
-  // If the language is the default, then ensure that no other languages have
-  // blank prefix codes.
-  if (!empty($language->default)) {
-    $prefixes = language_negotiation_url_prefixes();
-    foreach ($prefixes as $langcode => $prefix) {
-      if ($prefix == '' && $langcode != $language->langcode) {
-        $prefixes[$langcode] = $langcode;
-      }
-    }
-    language_negotiation_url_prefixes_save($prefixes);
-  }
 }
 
 /**
diff --git a/core/modules/language/language.negotiation.inc b/core/modules/language/language.negotiation.inc
index 48a8083..3173c19 100644
--- a/core/modules/language/language.negotiation.inc
+++ b/core/modules/language/language.negotiation.inc
@@ -435,6 +435,28 @@ function language_negotiation_url_prefixes() {
 }
 
 /**
+ * Update the list of prefixes from the installed languages.
+ */
+function language_negotiation_url_prefixes_update() {
+  $prefixes = language_negotiation_url_prefixes();
+  foreach (language_list() as $language) {
+    // the prefix for this language should be updated if its not assigned yet or it is set to ''
+    // ('' is a previous default language)
+    if (!isset($prefixes[$language->langcode]) || empty($prefixes[$language->langcode])) {
+      // if this is the default language, set the prefix to '', otherwise to the standard langcode
+      $prefixes[$language->langcode] = !empty($language->default)? '' : $language->langcode;
+    }
+    // else we keep the prefix a user has configured.
+
+    // make shure prefix is empty if this is the default. i.e. when changing default language
+    if (!empty($language->default)) {
+      $prefixes[$language->langcode] = '';
+    }
+  }
+  language_negotiation_url_prefixes_save($prefixes);
+}
+
+/**
  * Saves language prefix settings.
  */
 function language_negotiation_url_prefixes_save(array $prefixes) {