diff --git a/phpBB/language/en/app.php b/phpBB/language/en/app.php
index cb56015c30..6697532150 100644
--- a/phpBB/language/en/app.php
+++ b/phpBB/language/en/app.php
@@ -41,9 +41,6 @@ if (empty($lang) || !is_array($lang))
 $lang = array_merge($lang, array(
 	'CONTROLLER_ARGUMENT_VALUE_MISSING'	=> 'Missing value for argument #%1$s: <strong>%3$s</strong> in class <strong>%2$s</strong>',
 	'CONTROLLER_NOT_SPECIFIED'			=> 'No controller has been specified.',
-	'CONTROLLER_NOT_FOUND'				=> 'The requested page could not be found.',
 	'CONTROLLER_METHOD_NOT_SPECIFIED'	=> 'No method was specified for the controller.',
-	'CONTROLLER_SERVICE_NOT_GIVEN'		=> 'The controller "<strong>%s</strong>" must have a service specified in ./config/routing.yml.',
 	'CONTROLLER_SERVICE_UNDEFINED'		=> 'The service for controller "<strong>%s</strong>" is not defined in ./config/services.yml.',
-	'CONTROLLER_RETURN_TYPE_INVALID'	=> 'The controller object <strong>%s</strong> must return a Symfony\Component\HttpFoundation\Response object.',
 ));
diff --git a/phpBB/language/en/common.php b/phpBB/language/en/common.php
index e31164dfc8..aac4f2516e 100644
--- a/phpBB/language/en/common.php
+++ b/phpBB/language/en/common.php
@@ -218,8 +218,6 @@ $lang = array_merge($lang, array(
 	'ERROR'									=> 'Error',
 	'EXPAND_VIEW'						=> 'Expand view',
 	'EXTENSION'							=> 'Extension',
-	'EXTENSION_CONTROLLER_MISSING'		=> 'The extension <strong>%s</strong> is missing a controller class and cannot be accessed through the front-end.',
-	'EXTENSION_CLASS_WRONG_TYPE'		=> 'The extension controller class <strong>%s</strong> is not an instance of the phpbb_extension_controller_interface.',
 	'EXTENSION_DISABLED'				=> 'The extension <strong>%s</strong> is not enabled.',
 	'EXTENSION_DISABLED_AFTER_POSTING'	=> 'The extension <strong>%s</strong> has been deactivated and can no longer be displayed.',
 	'EXTENSION_DOES_NOT_EXIST'			=> 'The extension <strong>%s</strong> does not exist.',