diff --git a/lang/en/auth.php b/lang/en/auth.php
index 733a95fdde5..8533af90130 100644
--- a/lang/en/auth.php
+++ b/lang/en/auth.php
@@ -82,7 +82,6 @@ $string['errorminpasswordnonalphanum'] = 'Passwords must have at least {$a} non-
 $string['errorminpasswordupper'] = 'Passwords must have at least {$a} upper case letter(s).';
 $string['errorpasswordupdate'] = 'Error updating password, password not changed';
 $string['event_user_loggedin'] = 'User has logged in';
-$string['event_user_loggedin_desc'] = 'User {$a} has logged in';
 $string['forcechangepassword'] = 'Force change password';
 $string['forcechangepasswordfirst_help'] = 'Force users to change password on their first login to Moodle.';
 $string['forcechangepassword_help'] = 'Force users to change password on their next login to Moodle.';
diff --git a/lang/en/error.php b/lang/en/error.php
index 6bc3ac12c1c..a2508b4f514 100644
--- a/lang/en/error.php
+++ b/lang/en/error.php
@@ -503,6 +503,7 @@ $string['unknowncourse'] = 'Unknown course named "{$a}"';
 $string['unknowncourseidnumber'] = 'Unknown course ID "{$a}"';
 $string['unknowncoursesection'] = 'Unknown course section in course "{$a}"';
 $string['unknowncourserequest'] = 'Unknown course request';
+$string['unknownevent'] = 'Unknown event';
 $string['unknownfiletype'] = 'Error unknown filtertype';
 $string['unknowngroup'] = 'Unknown group "{$a}"';
 $string['unknownhelp'] = 'Unknown help topic {$a}';
diff --git a/lang/en/role.php b/lang/en/role.php
index 191d0f868a4..0ad7b6a31f9 100644
--- a/lang/en/role.php
+++ b/lang/en/role.php
@@ -181,6 +181,8 @@ $string['errorbadrolename'] = 'Incorrect role name';
 $string['errorbadroleshortname'] = 'Incorrect role short name';
 $string['errorexistsrolename'] = 'Role name already exists';
 $string['errorexistsroleshortname'] = 'Role name already exists';
+$string['eventroleassigned'] = 'Role assigned';
+$string['eventroleunassigned'] = 'Role unassigned';
 $string['existingadmins'] = 'Current site administrators';
 $string['existingusers'] = '{$a} existing users';
 $string['explanation'] = 'Explanation';
diff --git a/lib/classes/event/base.php b/lib/classes/event/base.php
index 0fb3b4ea061..1dc08ed5150 100644
--- a/lib/classes/event/base.php
+++ b/lib/classes/event/base.php
@@ -234,25 +234,21 @@ abstract class base implements \IteratorAggregate {
      *
      * Override in subclass, we can not make it static and abstract at the same time.
      *
-     * TODO: MDL-37658
-     *
-     * @return string|\lang_string
+     * @return string
      */
     public static function get_name() {
         // Override in subclass with real lang string.
         $parts = explode('\\', get_called_class());
         if (count($parts) !== 3) {
-            return 'unknown event';
+            return get_string('unknownevent', 'error');
         }
         return $parts[0].': '.str_replace('_', ' ', $parts[2]);
     }
 
     /**
-     * Returns localised description of what happened.
+     * Returns non-localised event description with id's for admin use only.
      *
-     * TODO: MDL-37658
-     *
-     * @return string|\lang_string
+     * @return string
      */
     public function get_description() {
         return null;
diff --git a/lib/classes/event/role_assigned.php b/lib/classes/event/role_assigned.php
index 79c7daa6ec2..6f9e8edb2f8 100644
--- a/lib/classes/event/role_assigned.php
+++ b/lib/classes/event/role_assigned.php
@@ -35,20 +35,18 @@ class role_assigned extends base {
     /**
      * Returns localised general event name.
      *
-     * @return string|\lang_string
+     * @return string
      */
     public static function get_name() {
-        //TODO: MDL-37658 localise
-        return 'Role assigned';
+        return get_string('eventroleassigned', 'role');
     }
 
     /**
-     * Returns localised description of what happened.
+     * Returns non-localised event description with id's for admin use only.
      *
-     * @return string|\lang_string
+     * @return string
      */
     public function get_description() {
-        //TODO: MDL-37658 localise
         return 'Role '.$this->objectid.' was assigned to user '.$this->relateduserid.' in context '.$this->contextid;
     }
 
diff --git a/lib/classes/event/role_unassigned.php b/lib/classes/event/role_unassigned.php
index 75501e8d3be..7dbfc647ec7 100644
--- a/lib/classes/event/role_unassigned.php
+++ b/lib/classes/event/role_unassigned.php
@@ -35,21 +35,19 @@ class role_unassigned extends base {
     /**
      * Returns localised general event name.
      *
-     * @return string|\lang_string
+     * @return string
      */
     public static function get_name() {
-        //TODO: MDL-37658 localise
-        return 'Role unassigned';
+        return get_string('eventroleunassigned', 'role');
     }
 
     /**
-     * Returns localised description of what happened.
+     * Returns non-localised event description with id's for admin use only.
      *
-     * @return string|\lang_string
+     * @return string
      */
     public function get_description() {
-        //TODO: MDL-37658 localise
-        return 'Role '.$this->objectid.'was unassigned from user '.$this->relateduserid.' in context '.$this->contextid;
+        return 'Role '.$this->objectid.' was unassigned from user '.$this->relateduserid.' in context '.$this->contextid;
     }
 
     /**
diff --git a/lib/classes/event/user_loggedin.php b/lib/classes/event/user_loggedin.php
index dd5a3227422..7cfc3f847ce 100644
--- a/lib/classes/event/user_loggedin.php
+++ b/lib/classes/event/user_loggedin.php
@@ -36,12 +36,12 @@ defined('MOODLE_INTERNAL') || die();
 class user_loggedin extends \core\event\base {
 
     /**
-     * Returns localised description of what happened.
+     * Returns non-localised event description with id's for admin use only.
      *
-     * @return \lang_string.
+     * @return string
      */
     public function get_description() {
-        return new \lang_string('event_user_loggedin_desc', '', $this->get_username());
+        return 'Userid ' . $this->userid . ' has logged in';
     }
 
     /**
@@ -57,10 +57,10 @@ class user_loggedin extends \core\event\base {
     /**
      * Return localised event name.
      *
-     * @return \lang_string
+     * @return string
      */
     public static function get_name() {
-        return new \lang_string('event_user_loggedin');
+        return new get_string('event_user_loggedin', 'auth');
     }
 
     /**