Index: src/wp-admin/js/common.js
===================================================================
--- src/wp-admin/js/common.js	(revision 26864)
+++ src/wp-admin/js/common.js	(working copy)
@@ -571,6 +571,19 @@
 
 				$( this ).parent( 'li' ).toggleClass( 'selected' );
 				event.preventDefault();
+			}).on( 'focusin.wp-responsive', function() {
+				if ( $adminmenu.data('wp-responsive') ) {
+					$wpwrap.addClass( 'wp-responsive-open' );
+				}
+			}).on( 'focusout.wp-responsive', function() {
+				if ( $adminmenu.data('wp-responsive') ) {
+					$wpwrap.removeClass( 'wp-responsive-open' );
+				}
+			}).find( 'a.wp-has-submenu' ).on( 'focus.wp-responsive-focus', function() {
+				// Open the submenu.
+				// This can be made to toggle the submenus, however there is a weird bug in Firefox:
+				// each other tab focuses the body instead of the next <a>...
+				$(this).parent('li').addClass( 'selected' );
 			});
 
 			self.trigger();
Index: src/wp-includes/admin-bar.php
===================================================================
--- src/wp-includes/admin-bar.php	(revision 26864)
+++ src/wp-includes/admin-bar.php	(working copy)
@@ -166,11 +166,8 @@
 	if ( is_admin() ) {
 		$wp_admin_bar->add_menu( array(
 			'id'    => 'menu-toggle',
-			'title' => '<span class="ab-icon"></span>',
+			'title' => '<span class="ab-icon"></span><span class="screen-reader-text">' . __( 'Menu' ) . '</span>',
 			'href'  => '#',
-			'meta'  => array(
-				'title' => __( 'Menu' ),
-			),
 		) );
 	}
 }