Redirect HTTPS to HTTP for a bilingual site
I would do the https to http redirect inside of .htaccess. Setting the base_url in settings.php will only fix it after the user clicks on a link. The landing page will still be https. I would use something like this in your .htaccess file:

RewriteCond %{HTTP_X_FORWARDED_PROTO} ^https$ [or]
RewriteCond %{HTTPS} ^on$
RewriteRule (.*) http://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]