Louis Carroll's 'Through the Looking Glass' (1872). To chortle is to a laugh at something which amuses or pleases you. It suggests a combination of the sound of chuckling (with amusement) and snorting (with derision).
Other Louis Caroll words and phrases in common use include: jaberwocky and galumping but, perhaps surprisingly, not mad as a hatter.
English Language 100 FAQ Teaching Pack - only £1.99 using discount code CQDWKF0