function mee_lang() {
$request_uri = parse_url($_SERVER['REQUEST_URI'], PHP_URL_PATH);
$url_info = parse_url($request_uri);
$uri = urldecode($url_info['path']);
$url = str_replace('/', '', $uri);
if ($url == 'eng') {
$link = '<a href="/'. $_SERVER['SCRIPT_NAME'] .'" title="По русски">RUS</a>';
} else {
$link = '<a href="/'.$url.'/'. $_SERVER['SCRIPT_NAME'] .'" title="in english">ENG</a>';
}
return $link;
}
<?php echo mee_lang(); ?>