diff --git a/wp-includes/l10n.php b/wp-includes/l10n.php
index 7408e1787..4a0a6409b 100644
--- a/wp-includes/l10n.php
+++ b/wp-includes/l10n.php
@@ -10,7 +10,7 @@ function get_locale() {
 		$locale = WPLANG;
 
 	if (empty($locale))
-		$locale = 'en_US';
+		$locale = '';
 
 	$locale = apply_filters('locale', $locale);
 
@@ -69,6 +69,9 @@ function load_default_textdomain() {
 	global $l10n;
 
 	$locale = get_locale();
+	if ( empty($locale) )
+		$locale = 'en_US';
+
 	$mofile = ABSPATH . LANGDIR . "/$locale.mo";
 
 	load_textdomain('default', $mofile);
@@ -76,6 +79,9 @@ function load_default_textdomain() {
 
 function load_plugin_textdomain($domain, $path = false) {
 	$locale = get_locale();
+	if ( empty($locale) )
+		$locale = 'en_US';
+
 	if ( false === $path )
 		$path = PLUGINDIR;
 
@@ -85,6 +91,8 @@ function load_plugin_textdomain($domain, $path = false) {
 
 function load_theme_textdomain($domain) {
 	$locale = get_locale();
+	if ( empty($locale) )
+		$locale = 'en_US';
 
 	$mofile = get_template_directory() . "/$locale.mo";
 	load_textdomain($domain, $mofile);