During my application's .htaccess file I've the next:

Options -Indexes

RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.+) index.php

A really lightweight file that puts all unmatched demands through index.php.

However, this application is really a social media website that I have been assigned with making multi-lingual. Therefore, Web addresses like www.example.com/profile/martin have to be converted directly into say, The spanish language, and can therefore become www.example.com/perfil/martin.

Therefore, my real question is: can you really rewrite a RewriteRule? In cases like this, I wish to rewrite /perfil/martin to /profile/martin, however have /profile/martin passed to index.php.

Adding the next line prior to the 'RewriteRule ^(.+) index.php' line should achieve what you would like.

RewriteRule perfil/(.*) profile/$1

I'd argue that you ought to do this inside your web app's URL routing code though, as opposed to the htaccess file.