title: Add language directory using .htaccess
body: <p>Hi Stackoverflow community,</p>
  
  <p>I've been reading through most of the other .htaccess questions, and tried different solutions on my .htaccess file but with no success.</p>
  
  <p>Here's the thing: I have a website (based on CodeIgniter) that already has a good SEO positioning. Now, the customer wants it translated to another language, but I dont want to lose that SEO so I thought of redirecting a URL like <a href="http://www.domain.com/contactUs" rel="nofollow">http://www.domain.com/contactUs</a> to <a href="http://www.domain.com/en/contactUs" rel="nofollow">http://www.domain.com/en/contactUs</a>, being (en) the current positioned language. CI would handle the other language as usual without problem. Im currently doing tests on localhost, so the following rules will have only "domain" instead of "domain.com".</p>
  
  <p>I've tried these Rewrite rules:</p>
  
  <pre><code>RewriteEngine on
  Options +FollowSymlinks
  
  RewriteCond ^(.*)/domain/(.*) !^/en/
  RewriteRule ^(.*)/domain/(.*)$ $1/domain/en/$2
  </code></pre>
  
  <p>I want the RewriteCond to filter URLs coming in the new language so that the RewriteRule is not executed. What am I doing wrong? </p>