Ni hao! Yo! Hola!

Dora the Explorer has unearthed Pirate Pig's treasure chest, saved Benny the Bull from a sinking hot-air balloon and, in a new hourlong episode, rescued mermaids from evil polluters. But perhaps the Latina heroine's greatest adventure is her continuing mission to introduce young fans to cultural diversity, an element that's as rare as magic coins on grown-up TV.

She's had some help. The presence of minorities in preschool programming dates back to the late '60s, when Gordon and Maria took up residence on "Sesame Street." Roughly half of the most popular shows among 2- to 5-year-olds today feature black, Hispanic or Asian characters in starring roles, including the "Dora" spinoff "Go, Diego, Go,"Handy Manny" and "Little Einsteins."Ni Hao, Kai-lan," debuting next year on Nick Jr., will mix in Mandarin words and phrases throughout tales about Chinese culture. PBS Kids' new series "Wordgirl" stars a 10-year-old caped crusader who is purposely drawn as having an "ambiguously ethnic origin," according to creator Dorothea Gillim, in hopes that she can serve as a role model for kids who might not regularly see themselves represented on television. Next year's "Team Umizumiz," co-created by Korean Soo Kim for Nick-offshoot Noggin, has a McGyver-inspired group of youngsters tackling math problems against an origami-based background.

That representation is in sharp contrast to prime time, in which minorities have the lead roles in only four prime-time series: "The Unit," K-Ville,"Ugly Betty" and "Cane."There is a chasm between what happens in children's television and what happens in adult programming," said Lesli Rotenberg, senior vice president for PBS Kids. "The kids today are growing up in a more ethnically diverse universe than any of us did."

In some ways, the increase of minority role models just makes good business sense, particularly when it comes to representing Hispanics. According to the U.S. Census Bureau, one of out every five preschoolers nationwide today is Latino.

But social responsibility also played a role in the development of TV trailblazer "Dora." The character was being shaped nine years ago as a Caucasian girl starring in a game show when Brown Johnson, executive vice president of Nickelodeon Preschool, attended a conference on children's media. She was struck by a study that concluded that no people from diverse backgrounds had leading roles in anything.

When she returned to the office, "Dora" began her transformation. By the time she hit the air in 2000, not only was the star Hispanic, but she routinely slipped into her native language, urging viewers to repeat common Spanish words and tag along with her on adventures rooted in Latino lore.

The show was an instant smash.

"If there was a myth that creating a show starring a Latina girl would have any obstacles in getting success, I think we destroyed it," said Chris Gifford, one of the show's creators.

Writers make sure that about a third of the episodes are culturally driven, which means it's not uncommon for Dora to step inside a Peruvian love story or a Puerto Rican folk tale. (Dora's specific roots are never revealed, which makes it easier for writers to sample from a variety of countries.) To drum up ideas, the show's writers and producers annually travel to Latin America to collect story ideas. The latest "Dora" adventure, premiering Monday night, involves cleaning up the environment and was inspired by the pollution the writers saw this year in the Amazon.

Not that there weren't stumbling blocks along the way. In the pilot episode, Dora had green eyes and light skin. The original Fisher-Price doll didn't look much like a Hispanic girl. Adjustments were quickly made.

When Bill Cosby saw the original art for "Little Bill," his animated preschool series currently airing on Noggin, he balked.

"He said, 'What is this?'" Johnson said. "All the characters are the same color. We're not the same color. We had to go back and create different shades."

The tinkering has paid off with kids of all races embracing these new stars.

Kathleen Herles, the 16-year-old Peruvian who provides Dora's voice, recalled appearing at a Latino book festival and being surprised to find an Asian family among the crowd.

"They were so amazing, saying how much they loved the show," she said. "They were all learning Spanish from it."

In the past, kids for whom English was a second language might have been the butt of playground teasing. But shows like "Dora" treat foreign languages like great gifts that can solve puzzles and even save the world.

"Kids with immigrant parents are often in the position of translating for their parents, which could be embarrassing," Johnson said. "We treat speaking another language like you have a magical power or a secret code you can pull out of your back pocket. It sounds hokey, but it makes these kids seem cool."

Prime-time adult shows have a lot of growing up to do before it's as progressive in terms of diversity. Unless the ratings for "Cane" get sweeter, TV will continue to struggle to produce a successful drama centered around a minority family. But there are signs of changes, particularly with the critical and popular success of "Ugly Betty," whose heroine is Mexican, and the casual interplay of different races on "Grey's Anatomy."

But it might take today's Dora fans to finally give television a proper cosmopolitan look.

"This generation is so different," Rotenberg said. "Maybe when they grow up, they'll change television."

njustin@startribune.com • 612-673-7431