Noun: The type of laughter that is silent then turns into a series of grunts.
This originated in Minneapolis, a group of kids wore the same set of shorts/pants everyday, and always made this kid laugh the same kind of way. Thus, his laugh matched the sound "Chortle" and "Chortle" acurately described the pant/shorts.
2."Mutherfucker, don't chortle when I'm talking to you, this is serious."
This term was frequently used in the Colorado high country by powder skiing hedonists late in the last millennium.