Index: src/wp-includes/formatting.php
===================================================================
--- src/wp-includes/formatting.php	(revision 30378)
+++ src/wp-includes/formatting.php	(working copy)
@@ -2238,14 +2238,14 @@
 	if ( $tz ) {
 		$datetime = date_create( $string, new DateTimeZone( $tz ) );
 		if ( ! $datetime )
-			return gmdate( $format, 0 );
+			return date_i18n( $format, false, true );
 		$datetime->setTimezone( new DateTimeZone( 'UTC' ) );
 		$string_gmt = $datetime->format( $format );
 	} else {
 		if ( ! preg_match( '#([0-9]{1,4})-([0-9]{1,2})-([0-9]{1,2}) ([0-9]{1,2}):([0-9]{1,2}):([0-9]{1,2})#', $string, $matches ) )
-			return gmdate( $format, 0 );
+ 			return date_i18n( $format, false, true );
 		$string_time = gmmktime( $matches[4], $matches[5], $matches[6], $matches[2], $matches[3], $matches[1] );
-		$string_gmt = gmdate( $format, $string_time - get_option( 'gmt_offset' ) * HOUR_IN_SECONDS );
+		$string_gmt  = date_i18n( $format, $string_time - get_option( 'gmt_offset' ) * HOUR_IN_SECONDS, true );
 	}
 	return $string_gmt;
 }
@@ -2269,14 +2269,14 @@
 	if ( $tz ) {
 		$datetime = date_create( $string, new DateTimeZone( 'UTC' ) );
 		if ( ! $datetime )
-			return date( $format, 0 );
+			return date_i18n( $format );
 		$datetime->setTimezone( new DateTimeZone( $tz ) );
 		$string_localtime = $datetime->format( $format );
 	} else {
 		if ( ! preg_match('#([0-9]{1,4})-([0-9]{1,2})-([0-9]{1,2}) ([0-9]{1,2}):([0-9]{1,2}):([0-9]{1,2})#', $string, $matches) )
-			return date( $format, 0 );
-		$string_time = gmmktime( $matches[4], $matches[5], $matches[6], $matches[2], $matches[3], $matches[1] );
-		$string_localtime = gmdate( $format, $string_time + get_option( 'gmt_offset' ) * HOUR_IN_SECONDS );
+			return date_i18n( $format );
+		$string_time      = gmmktime( $matches[4], $matches[5], $matches[6], $matches[2], $matches[3], $matches[1] );
+		$string_localtime = date_i18n( $format, $string_time + get_option( 'gmt_offset' ) * HOUR_IN_SECONDS, true );
 	}
 	return $string_localtime;
 }