There it is:
Lopadotemamachoselachogaleokranioleipsanodrimhypotirmmatosilphioparaomelitokatakechymenokichlepicossypho
phattoperisteralektryonoptekephalliokigklopeleiolagoiosiraiobaphetraganopterygon.
It's even bigger than pneumonoultramicroscopicsilicovolcanoconiosis!!
It's from Greece. Try to speak it...
EDIT:
According to Buffooner, there's another word EVEN bigger than this one. It's the chemical name for Titin. It's SO big that it reaches the maximum amount of letters in a post, so I can't put this word here.
Random joke:
Nappa: Vegeta, what does the scutter says about Titin's chemical name's length level?
Vegeta: It's OVER NINE THOUSAND!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
