diff --git a/wp-admin/network/site-new.php b/wp-admin/network/site-new.php
index 7882d0e378..4dd36392d4 100644
--- a/wp-admin/network/site-new.php
+++ b/wp-admin/network/site-new.php
@@ -65,10 +65,14 @@ if ( isset($_REQUEST['action']) && 'add-site' == $_REQUEST['action'] ) {
 	);
 
 	// Handle translation install for the new site.
-	if ( ! empty( $_POST['WPLANG'] ) && wp_can_install_language_pack() ) {
-		$language = wp_download_language_pack( wp_unslash( $_POST['WPLANG'] ) );
-		if ( $language ) {
-			$meta['WPLANG'] = $language;
+	if ( isset( $_POST['WPLANG'] ) ) {
+		if ( '' === $_POST['WPLANG'] ) {
+			$meta['WPLANG'] = ''; // en_US
+		} elseif ( wp_can_install_language_pack() ) {
+			$language = wp_download_language_pack( wp_unslash( $_POST['WPLANG'] ) );
+			if ( $language ) {
+				$meta['WPLANG'] = $language;
+			}
 		}
 	}
 
diff --git a/wp-includes/ms-functions.php b/wp-includes/ms-functions.php
index 113f37f284..ca8176124f 100644
--- a/wp-includes/ms-functions.php
+++ b/wp-includes/ms-functions.php
@@ -1092,7 +1092,10 @@ function wpmu_create_user( $user_name, $password, $email ) {
  * @return int|WP_Error Returns WP_Error object on failure, int $blog_id on success
  */
 function wpmu_create_blog( $domain, $path, $title, $user_id, $meta = array(), $site_id = 1 ) {
-	$defaults = array( 'public' => 0 );
+	$defaults = array(
+		'public' => 0,
+		'WPLANG' => get_site_option( 'WPLANG' ),
+	);
 	$meta = wp_parse_args( $meta, $defaults );
 
 	$domain = preg_replace( '/\s+/', '', sanitize_user( $domain, true ) );
@@ -1130,7 +1133,6 @@ function wpmu_create_blog( $domain, $path, $title, $user_id, $meta = array(), $s
 			update_option( $key, $value );
 	}
 
-	add_option( 'WPLANG', get_site_option( 'WPLANG' ) );
 	update_option( 'blog_public', (int) $meta['public'] );
 
 	if ( ! is_super_admin( $user_id ) && ! get_user_meta( $user_id, 'primary_blog', true ) )
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 290a2189f8..8af91b35b0 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7-alpha-38654';
+$wp_version = '4.7-alpha-38655';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.