example of a subdomain - lorem.example.com
the only one sinle page inside - index.php
and one $_GET param - named lang
lorem.example.com/en - should be interpreted as - lorem.example.com?lang=en
lorem.example.com/de - should be interpreted as - lorem.example.com?lang=de
here is my try, without success
RewriteEngine ON
RewriteRule ^(en)/?$ $1.php [QSA,NC,L]
RewriteRule ^(de)/?$ $1.php [QSA,NC,L]