Codeigniter multilingual site

Thank you

I was able to load the language file with hook
public function load() {
$CI =&get_instance();
if($_SERVER['SERVER_NAME'] == 'site.com')
{
$CI->lang->load('main','english');
}
}

But I have various language files
$CI->lang->load('main','english');
$CI->lang->load('home','english');
$CI->lang->load('about','english');

It's only loading 'main' language file which I have for menu, why it's not loading other files? Also isn't it possible to change the default language to other instead writing all filenames? Thanks