JOHN YANG: National Hispanic Heritage Month, which runs through October 15, celebrates a population of 64 million people that's diverse, growing and constantly changing.

But can a single term, whether it's Hispanic or Latino, describe a population of such varied ancestry, immigrant generations and geographic origin?

Mark Hugo Lopez is Director of Race and Ethnicity at the Pew Research Center, and Cristina Mora is a University of California, Berkeley sociology professor and author of Making Hispanics How Activists, Bureaucrats, and Media Constructed a New American.

Cristina, I want to start with you.

As the title of your book suggests, these terms are of relatively recent origin.

How did they come about?

How did they start?

CRISTINA MORA, University of California, Berkeley: Well, the idea of Hispanic itself has a very long history in sort of the colonial projects of Spanish colonization.

But the idea of it as a category in the United States that would be used to collect data and to identify a people really is at the latter half of the 20th century.

So really around the 1960s and 1970s, as Mexican, Puerto Rican, and even some Cuban populations rallied to sort of get together and ask that government start collecting their data.

And of course, if government's going to collect their data and the state's going to be able to track, for example, Hispanic poverty rates or Mexican and Puerto Rican employment rates, for example, it had to be called something, right?

And, you know, my work and the book tracks, really.

How did this category come to look at these populations, the Mexican American demands for data, the Puerto Rican demands for data, and see them as sort of a common set of communities that could be, you know, put together in an umbrella panethnic category that's large enough, right, to be compared to other groups like blacks and whites.

JOHN YANG: Mark, you've been polling this community since 2008.

What have you learned about how individuals identify themselves and what factors go into that decision?

MARK HUGO LOPEZ, Director of Race and Ethnicity Research, Pew Research Center: Yeah, it's really interesting.

We found that it's mostly the country of origin term that today Latino adults tell us that they use most often to describe themselves.

Perhaps a pan ethnic term might be the second most common thing that they use.

An American might be another term that they use.

But interestingly across immigrant generations, if you're an immigrant you're more likely to say your country of origin is how you most often describe yourself as Mexican or Cuban or Puerto Rican.

If instead if you're us Born to immigrant parents, you might be using both your country of origin but also American equally or perhaps one more than the other.

But by that third or higher generation U. S. born people of U.S. born parents, we begin to see really American is the most common term that's used most often by that population to describe themselves.

JOHN YANG: Cristina, are these two terms Latino and Hispanic, are they interchangeable?

CRISTINA MORA: For many, there are, and of course there are real preferences and there have always been real preferences.

We've seen since some of the first pollings in the 1980s around this issue that folks in LA, New York, even Houston in urban areas preferred the term Latino and folks in Colorado in more rural areas of Texas, even more rural areas of California preferred the term Hispanic.

So there was a real geographic connection to this.

And then there was likely a real generational connection to this with some generations really liking the term.

Even the predecessor of Hispanic Espanol with an o at the end having a preference for that.

And so we see not only geography, not only national origin, but also generation as being very well connected to certain labels over others.

So for example, folks have likely heard the term Afro-Latino, but you rarely ever hear the term Afro-Hispanic for example.

And so there are just ways that certain terms have been connected to preferences over time.

This, I think, just really connects to the fact that there's actually never been one term for which everyone has loved equally and has wholeheartedly been embraced.

You know, pan-ethnicity or these pan-racial categories are really secondary.

Yet just because they're secondary to national origin doesn't mean they're less important.

And they're quite powerful for how we organize the way we live in the world.

So, for example, I actually think of myself as Mexican-American, but also Chicana.

And I use the term Latina, and sometimes I use the term Latinx.

They're a much younger generation that grew up with different gender politics or sexuality politics than my generation grew up with.

I'll often use the term Latinx in many ways because these are bridges.

These are different ways of sort of speaking about this complicated and diverse heritage that we have.

JOHN YANG: Mark, what is your polling found about the use and acceptance of Latinx?

MARK HUGO LOPEZ: Yeah, it's really interesting.

So about four years ago in 2019, we asked Latino adults or Hispanic adults in the U.S. have they ever heard of the term Latinx?

75 percent or three quarters told us no, they hadn't.

We followed up with a question, though, among those who had heard the term, do they use it themselves to describe their identity?

And about 3 percent of Latino adults overall tell us that they use the term.

More recently, we've asked Latinos which term do they prefer to describe the population.

Hispanic more than Latino was preferred, but about 18 percent of Latino adults tell us they have no preference for either term, and only about 3 percent indicate Latinx is the term that they prefer to describe the population.

But what this speaks to is the diversity of the population.

As Cristina was noting, there are many different generations here, many different perspectives on how one chooses to identify, and it really is up to the individual how they choose to identify.

JOHN YANG: And you've also found in your polls, Mark, that as the generations go on, as the generations become more distant from the generation that immigrated, that identity sort of wanes a little bit.

MARK HUGO LOPEZ: That's right.

In fact, we've found that by that fourth generation, in fact, people who might have ancestry in Latin America may no longer even decide to call themselves Hispanic or Latino.

So it's really interesting to see how things can change across the generations, partly because of intermarriage as people grow up in households where one parent is Hispanic, one parent is not.

People may be proud of both heritages of their parents, but what about the grandchildren?

Next, maybe they may acknowledge that ancestry of Hispanic ancestry, but not necessarily say that they're Hispanic or Latino themselves.

JOHN YANG: Mark Hugo Lopez of the Pew Research Center and Cristina Mora of the University of California, Berkeley.

Thank you both very much.

MARK HUGO LOPEZ: Thank you.

CRISTINA MORA: Thank you.