Index: wp-admin/includes/class-wp-posts-list-table.php
===================================================================
--- wp-admin/includes/class-wp-posts-list-table.php	(revision 32281)
+++ wp-admin/includes/class-wp-posts-list-table.php	(working copy)
@@ -928,7 +928,7 @@
 						/* translators: used between list items, there is a space after the comma */
 						echo join( __( ', ' ), $out );
 					} else {
-						echo '—';
+						echo $taxonomy_object->labels->not_found;
 					}
 					echo '</td>';
 					break;
Index: wp-admin/includes/class-wp-media-list-table.php
===================================================================
--- wp-admin/includes/class-wp-media-list-table.php	(revision 32281)
+++ wp-admin/includes/class-wp-media-list-table.php	(working copy)
@@ -470,7 +470,7 @@
 				/* translators: used between list items, there is a space after the comma */
 				echo join( __( ', ' ), $out );
 			} else {
-				echo '&#8212;';
+				echo get_taxonomy( $taxonomy )->labels->not_found;
 			}
 			echo '</td>';
 			break;