Announce block selection changes manually on windows (#24299)

packages/block-editor/src/components/block-list/block-selection-button.js

@@ -14,12 +14,22 @@ import {
 	getBlockType,
 	__experimentalGetAccessibleBlockLabel as getAccessibleBlockLabel,
 } from '@wordpress/blocks';
+import { speak } from '@wordpress/a11y';
 
 /**
  * Internal dependencies
  */
 import BlockTitle from '../block-title';
 
+/**
+ * Returns true if the user is using windows.
+ *
+ * @return {boolean} Whether the user is using Windows.
+ */
+function isWindows() {
+	return window.navigator.platform.indexOf( 'Win' ) > -1;
+}
+
 /**
  * Block selection button component, displaying the label of the block. If the block
  * descends from a root block, a button is displayed enabling the user to select
@@ -63,6 +73,13 @@ function BlockSelectionButton( { clientId, rootClientId, ...props } ) {
 	// Focus the breadcrumb in navigation mode.
 	useEffect( () => {
 		ref.current.focus();
+
+		// NVDA on windows suffers from a bug where focus changes are not announced properly
+		// See WordPress/gutenberg#24121 and nvaccess/nvda#5825 for more details
+		// To solve it we announce the focus change manually.
+		if ( isWindows() ) {
+			speak( label );
+		}
 	}, [] );
 
 	function onKeyDown( event ) {