title: Website .htaccess language redirection only at the beginning of the session
body: <p>I'm using this code on my website's .htaccess for redirection based on browser language:</p>
  
  <pre><code>RewriteEngine On
  RewriteCond %{HTTP:Accept-Language} ^es [NC]
  RewriteCond %{QUERY_STRING} !(^|&amp;)lang=es [NC]
  RewriteRule ^$ https://www.example.com/ambienteTrabajo/?lang=es [L,R=301]
  </code></pre>
  
  <p>It works and redirects according to browser language, but it forces that all the time never letting you change to another one: if you try to manually select another language the site tries to load but gets immediately thrown back to the one that matches your browser configuration. </p>
  
  <p>I want visitors to be able to choose language at any time, so, is there any way I can make that code work redirecting only at the beginning of the session? </p>