location ~ \.css$ {
  add_header Content-Type "text/css; charset=utf-8";
  expires max;
  break;
}
location ~ \.gif$ {
  add_header Content-Type image/gif;
  expires max;
  break;
}
location ~ \.(html|php)$ {
  add_header Content-Language en;
  add_header Content-Type "text/html; charset=utf-8";
  expires max;
  break;
}
location ~ \.jpg$ {
  add_header Content-Type image/jpeg;
  expires max;
  break;
}
location ~ \.js$ {
  add_header Content-Type "application/javascript; charset=utf-8";
  expires max;
  break;
}
location ~ \.png$ {
  add_header Content-Type image/png;
  expires max;
  break;
}
location ~ \.xhtml$ {
  add_header Content-Language en;
  add_header Content-Type "application/xhtml+xml; charset=utf-8";
  expires max;
  break;
}
#add more as needed