Whenever this happens to me they are long and loud. Once it happened right next to my teacher and she yelled at me because she apparently already has enough to deal with because the boys do it all the time.
It's not quite the same thing, but when I hiccup, it's normal. However, sometimes I get the kind of hiccups where I have to make the burping action/ try to make myself burp, to get rid of the hiccup. It's strange. Normal though, I suppose.