WASHINGTON - Tia Thomas flipped through her note cards and said: "OK, I'm going to stump you."

"Loucheux," she said with a sly smile.

Unfazed, Matthew Evans correctly spelled "L-o-u-c-h-e-u-x," which describes a Native American tribe.

Tia threw her note cards on the table and folded her arms.

"And that was supposed to be one that stumped me!" Matthew said with a hint of bravado.

The pair of home-schooled 13-year-olds are the veterans of this week's Scripps National Spelling Bee, the only competitors who have made it this far four times before. They're among the favorites to win: The only returning speller who finished ahead of Tia last year is Matthew.

Their friendly rivalry has reached its fifth and final year as they age out of the competition.

"Actually, he is the person that I'm most anxious to beat this year," said Tia, from Coarsegold, Calif. "I really want to win this year."

"That would be a little disappointing," said Matthew, from Albuquerque, N.M. "But if she wins, that means she probably prepared better than me."

Tia and Matthew met yesterday at the eighth-floor lobby of the posh downtown hotel that is hosting the 81st edition of the competition. The bee begins in earnest today with a record 288 spellers competing in the oral preliminary round and concludes tomorrow night with a prime-time finish on ABC.

Should either Tia or Matthew win, the other will deserve a big thank-you. They have been comparing notes via instant-messaging every Friday night in the months leading up to the bee. Their two families had dinner together Tuesday night, a meal that was flush with a very rich vocabulary.

"There's definitely some pressure involved when the stakes are higher," said Tia's mother, Pamela Thomas. "It's her last year and Matthew's last year, and they've been friends for a long time and they both want to win. They're both extremely competitive."

Neither Matthew nor Tia made it out of the preliminary round their first two years, but in 2006 both decided to apply themselves more. Matthew has since finished 14th and sixth, and Tia has placed 22nd and eighth. *