OXON HILL, Md. -
The semifinal round of the Scripps National Spelling Bee is underway, with 42 youngsters vying for the title of champion spellers.
The contenders took the stage Thursday afternoon near Washington, D.C., amid hopes of advancing to the finals later in the evening.
LIVESTREAM: ESPN coverage of the National Spelling Bee
The winner will take more than $30,000 in cash and prizes.
This year's bee included the first vocabulary tests in the competition's history. The scores were combined with the onstage rounds to determine which spellers advanced.
San Diego County's bee representative, Giabao Tonthat, correctly spelled two words Wednesday, but his scores on the computer-based spelling and vocabulary tests did not qualify him for the next round.
Other Southern California contestants have also been eliminated.
Alan Shi, an eighth-grader at Sierra Vista Middle School in Irvine, has been eliminated, and so has Rebecca Baron, a student at Chatsworth Hills Academy. Another student from Riverside County's Coachella Valley was also eliminated.
This year's competition marked the first time the bee, which began with 281 contestants, incorporated vocabulary questions.
"It represents a deepening of the bee's commitment to its purpose -- to help students improve their spelling, increase their vocabularies, learn concepts and develop English usage that will help them all their lives," according to Paige Kimble, the bee's executive director and its 1981 champion.
The semifinal and championship rounds are being held Thursday, with a contestant eliminated after he or she misspells a word.
ESPN2 airs the semifinals from 11 a.m.-2 p.m. Thursday. The championship finals will be on ESPN from 5-7 p.m. Thursday.