Index: wp-admin/includes/schema.php
===================================================================
--- wp-admin/includes/schema.php	(revision 21651)
+++ wp-admin/includes/schema.php	(working copy)
@@ -901,6 +901,7 @@
 		'global_terms_enabled' => global_terms_enabled() ? '1' : '0',
 		'initial_db_version' => get_option( 'initial_db_version' ),
 		'active_sitewide_plugins' => array(),
+		'WPLANG' => get_locale(),
 	);
 	if ( ! $subdomain_install )
 		$sitemeta['illegal_names'][] = 'blog';