function get_client_language($availableLanguages, $default='en'){
if (isset($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {
$langs=explode(',',$_SERVER['HTTP_ACCEPT_LANGUAGE']);
//start going through each one
foreach ($langs as $value){
$choice=substr($value,0,2);
if(in_array($choice, $availableLanguages)){
return $choice;
}
}
}
return $default;
}