(I meant to say you're/they're.) I make this odd little high-pitched sound, that sounds a bit like I'm saying "Ha!" in a nasally tone. Otherwise, I'll burst out in a deep, obnoxious, "Ha!"
I have a silent laugh. Although I guess it's better than something high pitched and embarrassing, laughing without making a sound can also be quite awkward. It's like I'm on mute or sth.<br />
Oh I also "Pffffft" a lot