I want to be able to split the appearance and the content in a web site.

I know that php offers a way to do this. For example the phpbb.com does this with tables (.tbl files). Does anyone know how this is done and/or have sample code? I think this is the best way to handle the different language for example.

In other words, when a different language is to be displayed, the entire web content will not have to change, only the text. (And by language I mean French, German, Japanese and Korean ... not, Fortran, Pascal, Basic, Ada and C++).

People frequently use templates (.tpl) with a system like smarty which can be as complicated as it is simple.

Joomla/Mambo have a 2 file system, one gets the data, manages all that stuff. The other takes the data and creates output. In many cases they don't get the balance quite right but it's still good.