diff --git a/phpBB/includes/functions_user.php b/phpBB/includes/functions_user.php
index 9b0175694d..8a204995aa 100644
--- a/phpBB/includes/functions_user.php
+++ b/phpBB/includes/functions_user.php
@@ -1426,19 +1426,19 @@ function validate_match($string, $optional = false, $match = '')
 *
 * Tests whether a language name is valid and installed
 *
-* @param string $lang	The language string to test
+* @param string $lang_iso	The language string to test
 *
-* @return bool|string	Either false if validation succeeded or
-*						a string which will be used as the error message
-*						(with the variable name appended)
+* @return bool|string		Either false if validation succeeded or
+*							a string which will be used as the error message
+*							(with the variable name appended)
 */
-function validate_language($lang)
+function validate_language_iso_name($lang_iso)
 {
 	global $db;
 
 	$sql = 'SELECT lang_id
 		FROM ' . LANG_TABLE . "
-		WHERE lang_iso = '" . $db->sql_escape($lang) . "'";
+		WHERE lang_iso = '" . $db->sql_escape($lang_iso) . "'";
 	$result = $db->sql_query($sql);
 	$lang_id = (int) $db->sql_fetchfield('lang_id');
 	$db->sql_freeresult($result);
diff --git a/phpBB/includes/ucp/ucp_prefs.php b/phpBB/includes/ucp/ucp_prefs.php
index 76393530b2..13167b2b3d 100644
--- a/phpBB/includes/ucp/ucp_prefs.php
+++ b/phpBB/includes/ucp/ucp_prefs.php
@@ -65,7 +65,7 @@ class ucp_prefs
 
 					$error = validate_data($data, array(
 						'dateformat'	=> array('string', false, 1, 30),
-						'lang'			=> array('language'),
+						'lang'			=> array('language_iso_name'),
 						'tz'			=> array('num', false, -14, 14),
 					));
 
diff --git a/phpBB/includes/ucp/ucp_register.php b/phpBB/includes/ucp/ucp_register.php
index 76e02fd45b..13b9945851 100644
--- a/phpBB/includes/ucp/ucp_register.php
+++ b/phpBB/includes/ucp/ucp_register.php
@@ -56,7 +56,7 @@ class ucp_register
 		{
 			$use_lang = ($change_lang) ? basename($change_lang) : basename($user_lang);
 
-			if (!validate_language($use_lang))
+			if (!validate_language_iso_name($use_lang))
 			{
 				if ($change_lang)
 				{
@@ -210,7 +210,7 @@ class ucp_register
 					array('email')),
 				'email_confirm'		=> array('string', false, 6, 60),
 				'tz'				=> array('num', false, -14, 14),
-				'lang'				=> array('language'),
+				'lang'				=> array('language_iso_name'),
 			));
 
 			if (!check_form_key('ucp_register'))