diff --git a/wp-includes/class.wp-scripts.php b/wp-includes/class.wp-scripts.php
index 26fbd6da9b..531bb3a165 100644
--- a/wp-includes/class.wp-scripts.php
+++ b/wp-includes/class.wp-scripts.php
@@ -546,10 +546,13 @@ class WP_Scripts extends WP_Dependencies {
 			$json_translations = '{ "locale_data": { "messages": { "": {} } } }';
 		}
 
-		$output = '(function( translations ){' .
-					  'translations.locale_data.messages[""].domain = "' . $domain . '";' .
-					  'wp.i18n.setLocaleData( translations.locale_data.messages, "' . $domain . '" );' .
-				  '})(' . $json_translations . ');';
+		$output = <<<JS
+( function( domain, translations ) {
+	var localeData = translations.locale_data[ domain ] || translations.locale_data.messages;
+	localeData[""].domain = domain;
+	wp.i18n.setLocaleData( localeData, domain );
+} )( "{$domain}", {$json_translations} );
+JS;
 
 		if ( $echo ) {
 			printf( "<script type='text/javascript'>\n%s\n</script>\n", $output );
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 8b0adf2111..6c4af9c95e 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-alpha-44402';
+$wp_version = '5.1-alpha-44403';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.