RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^lang/(.*)$ index.php?lang=$1 [QSA,L]
RewriteRule ^mail/(.*)?$ index.php?page=mail&do=$1 [QSA,L]
RewriteRule ^([a-zA-Z_]+)/([0-9]+)/?$ index.php?page=$1&id=$2 [QSA,L]
RewriteRule ^([a-zA-Z_]+)/?$ index.php?page=$1 [QSA,L]