Index: wp-includes/l10n.php
===================================================================
--- wp-includes/l10n.php	(revision 23179)
+++ wp-includes/l10n.php	(working copy)
@@ -425,7 +425,13 @@
 		$path = WP_PLUGIN_DIR;
 	}
 
+	// Load the textdomain from the Plugin provided location, or plugin directory first
 	$mofile = $path . '/'. $domain . '-' . $locale . '.mo';
+	if ( $loaded = load_textdomain( $domain, $mofile ) )
+		return $loaded;
+
+	// Else, load textdomain from the Language directory
+	$mofile = WP_LANG_DIR . "/plugins/{$domain}-{$locale}.mo";
 	return load_textdomain( $domain, $mofile );
 }
 
@@ -441,7 +447,15 @@
 function load_muplugin_textdomain( $domain, $mu_plugin_rel_path = '' ) {
 	$locale = apply_filters( 'plugin_locale', get_locale(), $domain );
 	$path = WPMU_PLUGIN_DIR . '/' . ltrim( $mu_plugin_rel_path, '/' );
-	load_textdomain( $domain, trailingslashit( $path ) . "$domain-$locale.mo" );
+
+	// Load the textdomain from the Plugin provided location, or plugin directory first
+	$mofile = trailingslashit( $path ) . "$domain-$locale.mo";
+	if ( $loaded = load_textdomain( $domain, $mofile ) )
+		return $loaded;
+
+	// Else, load textdomain from the Language directory
+	$mofile = WP_LANG_DIR . "/plugins/{$domain}-{$locale}.mo";
+	return load_textdomain( $domain, $mofile );
 }
 
 /**
@@ -464,12 +478,12 @@
 
 	// Load the textdomain from the Theme provided location, or theme directory first
 	$mofile = "{$path}/{$locale}.mo";
-	if ( $loaded = load_textdomain($domain, $mofile) )
+	if ( $loaded = load_textdomain( $domain, $mofile ) )
 		return $loaded;
 
 	// Else, load textdomain from the Language directory
 	$mofile = WP_LANG_DIR . "/themes/{$domain}-{$locale}.mo";
-	return load_textdomain($domain, $mofile);
+	return load_textdomain( $domain, $mofile );
 }
 
 /**