The nannies’ most important credentials include speaking no English, only Spanish. The elementary schools are bilingual, or full immersion. Summer vacations unfold in, say, Colombia or Peru. The “¡Vamonos! Let’s Go!” CDs with Dora and Diego have been played so many times that finally they must be summarily disappeared for the sake of everyone’s sanity. Even the family dogs are bilingual, enthusing equally to “afuera” and “outside,” “juguete” and “toy.”

And yet, for parents going to such lengths, there will almost inevitably come a moment like the one experienced a few years ago by Glenda Harvey, a native of Puerto Rico. She speaks English without an accent, yet at home with her children, she speaks Spanish. Her husband, Steve Harvey, speaks English but fully supports the Spanish mission. By the age of 3, their elder son, Sebastian, was fluent in Spanish and English. Then he went to an English-language preschool.

“At some point, he would say, ‘Mom, I’d rather you speak English, please,’” Glenda Harvey recalled. “At which point I started crying and thinking that was the worst thing ever.”

Now Sebastian, 9, is enrolled in the Spanish-English program at the Washington International School. He’s still comfortable in both languages and reads Cervantes with his mother in Spanish. So far, so good.

A Latino presence

Washington feels more Latinized every day. The region’s Latino population rose 73 percent between 2000 and 2010, from 408,885 to 709,193. Hispanics are 15 percent of the population. There are bilingual signs in stores, Spanish advisories in Metro stations and airports, bilingual ATMs and bank tellers.

Spanish seems so very alive because it is fresh on the lips of so many new arrivals. Yet, simultaneously, the language is dying daily. Research shows that most grandchildren of Latino immigrants will sound like gringos.

Despite parents’ and grandparents’ best efforts, “Spanish appears to draw its last breath in the third generation,” said Ruben Rumbaut, professor of sociology at the University of California at Irvine, a leading expert in the survival rates of immigrant languages. He calls the United States “the world’s largest language graveyard” because of the cultural power of American English.

To beat the odds, a subset of high-achieving Latino parents in the Washington area is adding an especially heartfelt obligation to the suburban scramble for programmed activity: from ballet to soccer to piano — to various Spanish-language programs around the Beltway.

“It is very difficult to accomplish,” said Harvey, who, as a Puerto Rican, is not an immigrant but whose first language was Spanish. “I want them to really know who they are,” she said of her three children. “You do not understand the nuances of a culture until you can truly hear it and feel it the way you do through language.”

This region is home to the most affluent and one of the most highly educated Latino communities in the country. These established and worldly parents are perfectly bilingual themselves, at ease in two worlds. Keenly aware of the prospect of language death, they seek strategies to bequeath their own cultural agility to their children.

An idea is born

Like Harvey, Carmen Helena Ruzza is doing everything she can to help her two sons grow up fluent in Spanish as well as English. Ruzza is a Spanish instructor at American University who was raised in Venezuela and is married to a corporate finance director from Peru. They speak only Spanish to their sons Diego, 4, and Sebastian, 2, and are enrolling them in a Spanish culture program. Meanwhile, their children also know the siren appeal of Chuck E. Cheese’s and the “Merry Madagascar” ice spectacle at National Harbor.

“The challenge will be, even though they love what they have here [in the United States], they have to keep loving what we taught them,” Ruzza said.

Two mothers who went to greater lengths than most are Pilar O’Leary and Alexandra Migoya. They are former corporate lawyers who met as students at Georgetown University Law Center in the mid-1990s. They were producers of the noted 2008 video “Podemos con Obama” (“We Can With Obama”), featuring Latino celebrities singing and endorsing, in Spanish, candidate Barack Obama.

Around that time, each was looking for a culture-based Spanish-language program for her children. They couldn’t find one they liked and discovered how many friends faced the same issue. Therein lay a market.

Two years ago, they created Isabella & Ferdinand Spanish Language Adventures in Bethesda, which now has about 110 students.

“Unlike the past, where Latino immigrants often urged an English-only policy with their children in order to ensure assimilation, Hispanics are now eager to preserve their heritage and their language,” said O’Leary, whose mother is Colombian and whose father is a Spanish-speaking non-Latino who worked in Colombia.

Parents such as O’Leary’s and Migoya’s — Dominican mother, Spanish father — had more time to inculcate the language and culture almost exclusively at home. That doesn’t seem possible anymore.

As busy professionals who had intended to outsource some language grooming of their own children, O’Leary and Migoya realized the task is more than most parents can manage on their own.

“I wanted my children to know this is not just their mom’s weird background,” O’Leary said. “I wanted them to know this language connects to this amazing culture, all these significant artists and cultural heroes.”

The pair went so far as to produce a CD called “Ole & Play!” this year, featuring original songs in Spanish, performed by pop stars such as bilingual singer-songwriter Gaby Moreno, a Guatemalan who learned English from American blues records. It’s the anti-Dora product for weary parents: kid-friendly tunes with adult-tolerable content, such as musical portraits of artists Frida Kahlo, Diego Rivera and Fernando Botero and riffs on Don Quixote, the Taino indians and the Day of the Dead. More than 2,000 copies have been sold, and more than 1,000 Spanish teachers have downloaded songs for use in class.

“That was a huge success in our household,” said Andrea Garcia Hamilton, a Peruvian American with two young children.

“I could have done all this at home,” she said, but securing outside validation is a key part of the challenge. “I felt it was important for them to feel that others are learning about it, too. This isn’t just something you learn at home.”

Demand is so strong that Isabella & Ferdinand is expanding into educational software, summer language camps and winter dance and music camps. Spanish musician Fran Revert is the staff composer. Students in the regular program, ages 12 months to 10 years, are roughly split between Latinos and non-Latinos, with a mix of new learners and partially bilingual kids. Tuition ranges from $350 to $425 for 10 one-hour classes over 10 weeks.

Other extracurricular language programs in the area include the Escuela Argentina (the Argentine School) in Potomac and the Escuela Bolivia in Arlington County. Many parents also rely on immersion programs in area public school systems, charter schools and private schools.

A connection to their culture

At McLean High School, Spanish teacher Adam Stryker said that nearly a quarter of his students in some classes are “heritage language learners,” young people whose families have a Spanish-language background.

On back-to-school night, those parents tell him, “I really want to make sure my child doesn’t lose the language,” he said. “There’s more of a yearning for learning the heritage language than there was before.”

Many parents are trying to give their kids what they themselves missed. Alessia McIntosh’s mother is Cuban and married a non-Latino. Spanish wasn’t spoken much at home. The priority was achieving in English. Since then, McIntosh has studied to recover Spanish for herself, and now, with the enthusiastic of support of her non-Latino husband, Washington Redskin Rocky McIntosh, she is trying to instill Spanish in their two children.

“I want my kids to have an opportunity to understand the culture of their grandmother,” she said.

Families with Latino and non-Latino parents face the challenge of forging a bilingual future while honoring a bilingual past. “For us, our kids are not only Americans, they are also Colombians,” said Viviana Lopez Green, who is from Cartagena, while her husband, entrepreneur Shane Green, grew up in North Florida and has lived in Spain. “We want to keep that, not only as a fact but as a reality in their lives.”

For now, they plan to send Gabriela, 4, and Javier, 2, to the public elementary school in their Chevy Chase neighborhood. They also employ a Spanish-speaking nanny, and Gabriela has gone to Isabella & Ferdinand and Spanish summer camp. “She already speaks Spanish perfectly,” Lopez Green said. “I want her to be able to read and write. I want my daughter to be able to enjoy a Gabriel Garcia Marquez novel the same way I enjoy it.”

Rumbaut, the chronicler of language death, holds out some hope that these parents will beat the cultural odds. “They have the resources to at least make a stand for a while,” he said.

He, of all people, knows had hard it is. He immigrated from Cuba at 12. He and his Mexican American wife resolved to raise a fluently bilingual child. Young Ruben Dario Rumbaut never heard his father utter an English word until the boy was nearly 6. When he was almost 9, the family moved from Detroit, where the father was teaching, to Southern California, so the child would have a more Latino environment, and they enrolled him in a Catholic school with a strong Spanish program.

“I was as extreme as you can get,” the father said.

And yet, he considers himself only partially successful. Now his son is 18. In adolescence, he started feeling less confident in Spanish. He began responding to his parents in English.

“He has as solid a base in that second language as I could give him,” the elder Rumbaut said. “Now it’s up to him and his surroundings. It takes a village to raise a language.”

A glimmer of hope for American bilingualism is visible in Rumbaut’s research. The second- and third-generation youths who drift from the heritage language as self-conscious teens begin to value it in their mid-20s and early 30s. It’s a job credential and a touchstone of identity.

“They emerge asking, ‘Mom and Dad, why didn’t you teach me Spanish?’ And Mom and Dad say, ‘We did, but you weren’t listening!’ ”

Staff researcher Jennifer Jenkins contributed to this report.