"How hard a child works is a very individual factor," said Ms Kimble, who won the national bee in 1981.

"But what might be happening (with Indian American contestants) is that there might be perseverance for the National Spelling Bee goal over a longer period of time," she was quoted as saying by the Washington Post.

Indeed, of the Indian-American champions over the past 15 years, only one, Pratyush Buddiga, won on a first trip to the national bee in 2002.

The others won after multiple trips, including last year's co-champ, Sriram Hathwar, who made it to the national bee five times before winning, and Kavya Shivashankar in 2009 and Sameer Mishra in 2008, who both won on their fourth trips.

Ms Kimble and other bee organizers were appalled by the reaction to last year's contest, when Sriram, then 14, and his co-winner Ansun Sujoe, then 13, were greeted with a barrage of racist comments on Facebook and Twitter.

"We certainly followed the coverage last year and we are aware of Twitter posts that are not nice, that indicate that we have a long way to go as a country in embracing all of our immigrant population," Ms Kimble said.

Despite the backlash, for Indian Americans the growing spelling dynasty has become a source of great pride.

Ms Shankar points out that immigrants from India, who are the parents and grandparents of today's spellers, are typically well-educated professionals and driven to succeed.

In a country where sports is king for many young people, Buddiga said the bee offered competition that coincided with academic goals set by Indian American families.

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