What's a good method to add a culture prefix once to a path?
The answer is: not at all. If you don't want your users to know that your structure is like that, then don't show it to them. That means, when you get a request for
.com.br, you internally check the
HTTP_HOST, and assign a variable to your script, which can then execute based on the language.
To be perfectly honest, I think
mod_rewrite is a waste of time for this. If your site is written in any half-decent scripting language, you can have your script lookup the
HTTP_HOST in a database, which matches to a language, and you can continue from there.
mod_rewrite (and thus most
.htaccess directives) don't really scale dynamically: what if, when they hit the
.com version of your website, you want to lookup their IP and redirect them to the most appropriate suffix based on their approximate location? You'll have a tough time doing that with just