diff --git a/src/js/_enqueues/admin/post.js b/src/js/_enqueues/admin/post.js
index 2ca60e7c4b..0fc9a17d21 100644
--- a/src/js/_enqueues/admin/post.js
+++ b/src/js/_enqueues/admin/post.js
@@ -4,7 +4,7 @@
  * @output wp-admin/js/post.js
  */
 
- /* global ajaxurl, wpAjax, setPostThumbnailL10n, postboxes, pagenow, tinymce, alert, deleteUserSetting, ClipboardJS */
+ /* global ajaxurl, wpAjax, postboxes, pagenow, tinymce, alert, deleteUserSetting, ClipboardJS */
  /* global theList:true, theExtraList:true, getUserSetting, setUserSetting, commentReply, commentsBox */
  /* global WPSetThumbnailHTML, wptitlehint */
 
@@ -145,7 +145,7 @@ window.wp = window.wp || {};
 			 */
 			function(str){
 			if ( str == '0' ) {
-				alert( setPostThumbnailL10n.error );
+				alert( __( 'Could not set that as the thumbnail image. Try a different attachment.' ) );
 			} else {
 				WPSetThumbnailHTML(str);
 			}
diff --git a/src/js/_enqueues/admin/set-post-thumbnail.js b/src/js/_enqueues/admin/set-post-thumbnail.js
index 0f3849af34..5f5f565564 100644
--- a/src/js/_enqueues/admin/set-post-thumbnail.js
+++ b/src/js/_enqueues/admin/set-post-thumbnail.js
@@ -2,23 +2,23 @@
  * @output wp-admin/js/set-post-thumbnail.js
  */
 
-/* global setPostThumbnailL10n, ajaxurl, post_id, alert */
+/* global ajaxurl, post_id, alert */
 /* exported WPSetAsThumbnail */
 
 window.WPSetAsThumbnail = function( id, nonce ) {
 	var $link = jQuery('a#wp-post-thumbnail-' + id);
 
-	$link.text( setPostThumbnailL10n.saving );
+	$link.text( wp.i18n.__( 'Saving…' ) );
 	jQuery.post(ajaxurl, {
 		action: 'set-post-thumbnail', post_id: post_id, thumbnail_id: id, _ajax_nonce: nonce, cookie: encodeURIComponent( document.cookie )
 	}, function(str){
 		var win = window.dialogArguments || opener || parent || top;
-		$link.text( setPostThumbnailL10n.setThumbnail );
+		$link.text( wp.i18n.__( 'Use as featured image' ) );
 		if ( str == '0' ) {
-			alert( setPostThumbnailL10n.error );
+			alert( wp.i18n.__( 'Could not set that as the thumbnail image. Try a different attachment.' ) );
 		} else {
 			jQuery('a.wp-post-thumbnail').show();
-			$link.text( setPostThumbnailL10n.done );
+			$link.text( wp.i18n.__( 'Done' ) );
 			$link.fadeOut( 2000 );
 			win.WPSetThumbnailID(id);
 			win.WPSetThumbnailHTML(str);
diff --git a/src/js/_enqueues/wp/media/editor.js b/src/js/_enqueues/wp/media/editor.js
index b74780d928..cc0167682a 100644
--- a/src/js/_enqueues/wp/media/editor.js
+++ b/src/js/_enqueues/wp/media/editor.js
@@ -627,7 +627,7 @@
 				_wpnonce:     settings.post.nonce
 			}).done( function( html ) {
 				if ( '0' === html ) {
-					window.alert( window.setPostThumbnailL10n.error );
+					window.alert( wp.i18n.__( 'Could not set that as the thumbnail image. Try a different attachment.' ) );
 					return;
 				}
 				$( '.inside', '#postimagediv' ).html( html );
diff --git a/src/wp-includes/script-loader.php b/src/wp-includes/script-loader.php
index 04994da384..f0404830bd 100644
--- a/src/wp-includes/script-loader.php
+++ b/src/wp-includes/script-loader.php
@@ -1186,6 +1186,7 @@ function wp_default_scripts( $scripts ) {
 	$scripts->set_translations( 'media-views' );
 
 	$scripts->add( 'media-editor', "/wp-includes/js/media-editor$suffix.js", array( 'shortcode', 'media-views' ), false, 1 );
+	$scripts->set_translations( 'media-editor' );
 	$scripts->add( 'media-audiovideo', "/wp-includes/js/media-audiovideo$suffix.js", array( 'media-editor' ), false, 1 );
 	$scripts->add( 'mce-view', "/wp-includes/js/mce-view$suffix.js", array( 'shortcode', 'jquery', 'media-views', 'media-audiovideo' ), false, 1 );
 
@@ -1287,16 +1288,7 @@ function wp_default_scripts( $scripts ) {
 		$scripts->set_translations( 'image-edit' );
 
 		$scripts->add( 'set-post-thumbnail', "/wp-admin/js/set-post-thumbnail$suffix.js", array( 'jquery' ), false, 1 );
-		did_action( 'init' ) && $scripts->localize(
-			'set-post-thumbnail',
-			'setPostThumbnailL10n',
-			array(
-				'setThumbnail' => __( 'Use as featured image' ),
-				'saving'       => __( 'Saving...' ), // No ellipsis.
-				'error'        => __( 'Could not set that as the thumbnail image. Try a different attachment.' ),
-				'done'         => __( 'Done' ),
-			)
-		);
+		$scripts->set_translations( 'set-post-thumbnail' );
 
 		/*
 		 * Navigation Menus: Adding underscore as a dependency to utilize _.debounce