diff --git a/lang/en/auth.php b/lang/en/auth.php
index 6c892f91077b6..4d22529d05890 100644
--- a/lang/en/auth.php
+++ b/lang/en/auth.php
@@ -130,6 +130,7 @@
 
 If you are not sure what the words are, you can try getting another CAPTCHA or an audio CAPTCHA.';
 $string['recaptcha_link'] = 'auth/email';
+$string['security_question'] = 'Security question';
 $string['selfregistration'] = 'Self registration';
 $string['selfregistration_help'] = 'If an authentication plugin, such as email-based self-registration, is selected, then it enables potential users to register themselves and create accounts. This results in the possibility of spammers creating accounts in order to use forum posts, blog entries etc. for spam. To avoid this risk, self-registration should be disabled or limited by <em>Allowed email domains</em> setting.';
 $string['sha1'] = 'SHA-1 hash';
diff --git a/login/signup_form.php b/login/signup_form.php
index 71ad670a12360..8a0dbedd59193 100644
--- a/login/signup_form.php
+++ b/login/signup_form.php
@@ -89,7 +89,7 @@ function definition() {
         }
 
         if ($this->signup_captcha_enabled()) {
-            $mform->addElement('recaptcha', 'recaptcha_element', get_string('recaptcha', 'auth'), array('https' => $CFG->loginhttps));
+            $mform->addElement('recaptcha', 'recaptcha_element', get_string('security_question', 'auth'), array('https' => $CFG->loginhttps));
             $mform->addHelpButton('recaptcha_element', 'recaptcha', 'auth');
         }