Twelve-year-old Mignon Tsai of Abbotsford, B.C., was tripped up by the word "macropodid" during the nail-biter of a semifinal.
In the next round, Jennifer Mong of St. John's, N.L. — after nailing the word "lymphopoiesis" earlier in the day — flubbed the spelling of "vellon" by adding an "e" on the end, concluding her run at the famous spelling bee.
The girls were among 50 competitors to make it to the semifinals following two days of often tense competition that saw spelling bee officials challenge them with progressively more difficult words as the contest proceeded.
Many of those words, with origins in foreign languages, would confound adult Mensa members, and yet most of the schoolchildren, including Tsai and Mong, approached the microphone with poise, confidence — and no small amount of courage amid the glare of television cameras and a time limit to spell their words.
Almost all of them asked the spelling bee's host a series of questions about the origin of their word and its definition, and then gamely attempted to spell it right.
As Round Four of the competition that got underway Thursday morning, Tsai took to the stage to spell "oxyacetylene" correctly, while Mong aced "berserker."
About 15 spellers were expected to remain standing by the end of the semifinal, and will advance later Thursday to the final, to be broadcast live on ESPN from a glittering, waterfront conference centre in National Harbor, Md., just down the Potomac River from the U.S. capital.
Mong, Tsai and Zhongtian Wang, 11, of Windsor, Ont., competed at the bee a year after Canadian Laura Newcombe took second place at the world-renowned contest. Wang was eliminated Wednesday.
Newcombe, now 13, came enticingly close to winning the spelling bee last year in a tense final round. The Torontonian was tripped up by the Greek word "sorites."
Canadians have been a strong presence at the Scripps competition for years, and have had several close calls. Nate Gartke and Finola Hackett of Alberta were previous runners-up.
The winner of the spelling bee will take home more than US$40,000 in cash and scholarship money.
This year's competition included schoolkids not just from the U.S. and Canada, but from the Bahamas, China, Ghana, Jamaica, Japan, New Zealand and South Korea.
The 2012 contest also featured its youngest-ever speller — six-year-old Lori Anne Madison from Woodbridge, Va.
The girl spelled her first word correctly on Wednesday — "dirigible" — but flubbed her second word, "ingluvies," and was eliminated from competition.
Most spellers at the bee are between 12 and 14 years old.