Index: src/js/_enqueues/lib/link.js
===================================================================
--- src/js/_enqueues/lib/link.js	(revision 43540)
+++ src/js/_enqueues/lib/link.js	(working copy)
@@ -509,7 +509,7 @@
 			var waiting,
 				search = inputs.search.val() || '';
 
-			if ( search.length > 2 ) {
+			if ( search.length > parseInt( wpLinkL10n.lengthForSearchInternalLinks, 10 ) ) {
 				rivers.recent.hide();
 				rivers.search.show();
 
Index: src/wp-includes/script-loader.php
===================================================================
--- src/wp-includes/script-loader.php	(revision 43540)
+++ src/wp-includes/script-loader.php	(working copy)
@@ -558,13 +558,14 @@
 	$scripts->add( 'wplink', "/wp-includes/js/wplink$suffix.js", array( 'jquery', 'wp-a11y' ), false, 1 );
 	did_action( 'init' ) && $scripts->localize(
 		'wplink', 'wpLinkL10n', array(
-			'title'          => __( 'Insert/edit link' ),
-			'update'         => __( 'Update' ),
-			'save'           => __( 'Add Link' ),
-			'noTitle'        => __( '(no title)' ),
-			'noMatchesFound' => __( 'No results found.' ),
-			'linkSelected'   => __( 'Link selected.' ),
-			'linkInserted'   => __( 'Link inserted.' ),
+			'title'                        => __( 'Insert/edit link' ),
+			'update'                       => __( 'Update' ),
+			'save'                         => __( 'Add Link' ),
+			'noTitle'                      => __( '(no title)' ),
+			'noMatchesFound'               => __( 'No results found.' ),
+			'linkSelected'                 => __( 'Link selected.' ),
+			'linkInserted'                 => __( 'Link inserted.' ),
+			'lengthForSearchInternalLinks' => _x( '2', 'search internal links' ),
 		)
 	);