Index: src/wp-includes/theme.php
===================================================================
--- src/wp-includes/theme.php	(revision 30745)
+++ src/wp-includes/theme.php	(working copy)
@@ -1615,7 +1615,9 @@
 		case 'title-tag' :
 			// Can be called in functions.php but must happen before wp_loaded, i.e. not in header.php.
 			if ( did_action( 'wp_loaded' ) ) {
-				_doing_it_wrong( "add_theme_support( 'title-tag' )", sprintf( _x( 'You need to add theme support before %s.', 'action name' ), '<code>wp_loaded</code>' ), '4.1.0' );
+				/* translators: 1: Theme support 2: hook name */
+				_doing_it_wrong( "add_theme_support( 'title-tag' )", sprintf( __( 'Theme support for %1$s should be registered before the %2$s hook.' ),
+					'<code>title-tag</code>', '<code>wp_loaded</code>' ), '4.1' );
 
 				return false;
 			}