The spelling bee can draw on words from all languages, but if your interest is whetted, the library has a number of books on etymology, including:
Spell It Out: the Curious, Enthralling and Extraordinary Story of English Spelling
Spellbound : the Surprising Origins and Astonishing Secrets of English Spelling
Our Magnificent Bastard Tongue: the Untold History of English
Reading the OED: One Man, One Year, 21,730 pages.
Lastly, there's always The Professor and the Madman about the collaboration which led to the Oxford English Dictionary.
Last year's winning word was "knaidel". Tune in to ESPN at 6 p.m. (or watch the live stream) to watch the finals and root for this year's stellar spellers!