Patricia Arias came to New York from Colombia 19 years ago, but she speaks English only to the children she teaches at a church agency. Her husband, Jorge Ignacio, does so only when he talks to customers at the parking garage in Lower Manhattan where he works. In their Queens neighborhood, Jackson Heights, they shop only at the many stores where the proprietors speak Spanish. They watch Spanish newscasts on Univision and Spanish soap operas on Telemundo. "I don't have any American friends," said Mrs. Arias, 33.
 

The Ariases' almost totally Hispanic world is one in which Richard Rodriguez would be a stranger. His parents migrated from Puerto Rico, and he lives in a Latino neighborhood in North Bergen, N.J., but he was born in Hoboken and grew up speaking English. He likes salsa and hip-hop. He was raised as a Roman Catholic but says he thinks of himself now as only "spiritual." He speaks Spanglish to his grandparents but watches MTV and BET.
 

"I'm definitely Latino but Americanized," said Mr. Rodriguez, 26, a promotions manager for Urban Latino, a bimonthly magazine geared to second-generation Latinos. "It's a fusion of Latin culture and American culture," he said of his background.
 

Mr. Rodriguez and the Ariases share a Hispanic identity, but they represent two very significant facets of Latinos in the New York metropolitan region. And the differences between them are increasingly evident. Language and nativity are two of the most stark lines of demarcation, with Spanish the dominant language among many foreign-born Latinos, and English generally the choice of those born or reared in the United States by Hispanic parents. This dichotomy within the country's rapidly expanding Latino population presents a quandary for advertisers, political candidates and anyone else whose business it is to pitch products or policies to Latinos: Which group are you pitching to, and what, besides language, are the differences between them?
 

Some strategists, like José Ithier, who worked on Gov. George E. Pataki's re-election campaign last year, trying to shape the right message in the right language for the right audience, try to cover all the bases.
 

Mr. Ithier, now an economic development official with the governor's office in New York City, said that Mr. Pataki recorded radio and television ads in English and Spanish, distributed fliers and mailers that were bilingual and covered an array of issues, and opened speeches and community appearances with remarks in Spanish and then switched to English.
 

"You'd be crazy not to do both equally, because it's such a mesh," Mr. Ithier said.

But some advertisers, like the recently formed New Generation Latino Consortium, say they favor focusing more on Latinos who are bilingual or for whom English is the dominant language. They say that Latinos born in the United States are now the fastest-growing segment of the Hispanic population and that they are getting more attention now even in fields where they have long been neglected.
 

The consortium, a group of advertising and media companies in New York and Miami, argues that these Latinos should be reached with culturally sensitive ads the way other niche markets, like African-Americans, have been.

In New York City, Latinos make up 27 percent of the population. National data from the 2000 census on nativity and language spoken at home are not yet available, but the numbers for selected states like New York and New Jersey show that native-born Latinos slightly outnumber those who immigrated, and that the great majority of all Latinos speak both English and Spanish. Nearly 70 percent of the country's 37 million Latinos are under 35, including immigrant children who usually need only a few years to become fluent in English and bicultural. To reach this population, the language increasingly being used is English.
 

A national cable channel, Telemundo's mun2, is among the newer media outlets now testing cultural relevance by offering talk, music and news magazine programs mainly in English directed toward Latinos in the 18-to-34 age group.

In 2001 the publisher HarperCollins began the imprint Rayo, which publishes Latino authors mostly in English.
 

"We were invisible, as if we didn't exist," Rayo's editorial director, Rene Alegria, said of his market. "People forget we're American."
 

In a major national survey last year of about 4,200 adults, the Pew Hispanic Center, a research organization in Washington, and the Kaiser Family Foundation found that on questions of attitude and social issues, native and immigrant Latinos differed sharply, reflecting the prevalent sensibilities of either the United States or Latin America.
 

On issues like divorce, abortion and homosexuality, for example, foreign-born respondents were much more conservative than native-born or American-reared Latinos, whose views were more in sync with those of non-Hispanic whites and blacks, the survey showed.
 

"A second-generation English-speaking Dominican in New York will have more in common with a second-generation English-speaking Mexican in Los Angeles than with a recently arrived Spanish-speaking Dominican in New York," said the Pew Center's director, Roberto Suro.
 

Mr. Ithier, the Pataki campaign strategist, said that immigrant Latinos generally want to hear about immigration, citizenship and workplace issues, and the native born are mostly interested in issues related to education, health and quality of life.
 

So handing out fliers in Spanish about immigration policy at a Cinco de Mayo event was a safe bet, he said, because such an event would be crowded with Mexican immigrants. But what to do with a list of Spanish-surnamed registered voters, which would include citizens by both birth and naturalization, that a candidate wants to reach through direct mail?
 

"You have a Spanish surname, but what are you?" said Mr. Ithier, who unlike his boss is a Democrat, and who was chief of staff for Fernando Ferrer, when he was Bronx borough president. "It's hard to tell."
 

In fact, the Pew survey showed, Latinos get closer to the mainstream in views and attitudes the farther away they get from their immigrant roots. One telling survey result: the concept of fatalism the sense, quite common in Latin America but not in American culture, that a person does not have control over the future was embraced by 59 percent of Spanish-dominant Latinos, but by only 24 percent of Latinos who speak mostly English.
 

Yet, all Latinos share certain views that set them apart from African-Americans and non-Hispanic whites. For example, the survey found that most Latinos are willing to pay higher taxes for more government services, compared with only 35 percent of non-Hispanic whites and 43 percent of African-Americans who were willing to do the same.
 

But a cultural divide is sometimes found even in the same household.
 

Take the family of Vianni Gomez, an 18-year-old Dominican who lives in Harlem with her parents, two younger brothers and grandmother. She moved here barely four years ago, but she and her 15-year-old brother already speak mostly English to each other, even though her parents understand little English and their grandmother understands none. The siblings also shun Spanish-language television for shows like "American Idol," and neighborhood clothing stores with names like El Mundo for Macy's.
 

But Ms. Gomez's parents, Radhames, 49, and Claricia, 47, said that despite wanting to make their life in New York they want to maintain a tight rein on how Americanized their children become. Their daughter, who is studying psychology at City College, has a curfew of 11 p.m. when she goes out with friends, for instance.
 

"Over there there's more discipline," Mrs. Gomez said, referring to the Dominican Republic. "We want her to ask permission to go out with friends. We want to know where she is."
 

Ms. Gomez, who said she has had to leave parties while all her friends stayed, confirmed that "at 9 p.m. I know my phone is going to ring. My father: `Where are you at?' It's like two different worlds."