diff --git a/wp-includes/class.wp-scripts.php b/wp-includes/class.wp-scripts.php
index 42374815d0..e843233cbc 100644
--- a/wp-includes/class.wp-scripts.php
+++ b/wp-includes/class.wp-scripts.php
@@ -546,7 +546,8 @@ class WP_Scripts extends WP_Dependencies {
 		}
 
 		$output = '(function( translations ){' .
-					  'wp.i18n.setLocaleData( translations.locale_data, "' . $domain . '" );' .
+					  'translations.locale_data.messages[""].domain = "' . $domain . '";' .
+					  'wp.i18n.setLocaleData( translations.locale_data.messages, "' . $domain . '" );' .
 				  '})(' . $json_translations . ');';
 
 		if ( $echo ) {
diff --git a/wp-includes/script-loader.php b/wp-includes/script-loader.php
index 5699810ef4..6dd77f46b2 100644
--- a/wp-includes/script-loader.php
+++ b/wp-includes/script-loader.php
@@ -319,7 +319,7 @@ function wp_default_packages_scripts( &$scripts ) {
 		'html-entities'                      => array( 'wp-polyfill' ),
 		'i18n'                               => array( 'wp-polyfill' ),
 		'is-shallow-equal'                   => array( 'wp-polyfill' ),
-		'keycodes'                           => array( 'lodash', 'wp-polyfill' ),
+		'keycodes'                           => array( 'lodash', 'wp-polyfill', 'wp-i18n' ),
 		'list-reusable-blocks'               => array(
 			'lodash',
 			'wp-api-fetch',
@@ -361,11 +361,28 @@ function wp_default_packages_scripts( &$scripts ) {
 		'wordcount'                          => array( 'wp-polyfill' ),
 	);
 
+	$package_translations = array(
+		'api-fetch'            => 'default',
+		'blocks'               => 'default',
+		'block-library'        => 'default',
+		'components'           => 'default',
+		'edit-post'            => 'default',
+		'editor'               => 'default',
+		'format-library'       => 'default',
+		'keycodes'             => 'default',
+		'list-reusable-blocks' => 'default',
+		'nux'                  => 'default',
+	);
+
 	foreach ( $packages_dependencies as $package => $dependencies ) {
 		$handle = 'wp-' . $package;
 		$path   = "/wp-includes/js/dist/$package$suffix.js";
 
 		$scripts->add( $handle, $path, $dependencies, false, 1 );
+
+		if ( isset( $package_translations[ $package ] ) ) {
+			$scripts->set_translations( $handle, $package_translations[ $package ] );
+		}
 	}
 }
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index cfefcead9f..ccd116e0d2 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-alpha-44238';
+$wp_version = '5.1-alpha-44239';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.