IN the Edin Espino family, late of Guatemala and now living in one of southwest Houston's sprawling, immigrant-filled apartment complexes, the best English is spoken by 4 1/2 -year-old preschooler Edin Jr.

The senior Espino, 27, understands enough to get by at his two jobs, one in a grocery store produce section and another at a nearby restaurant, but he can't hold a conversation. His wife, Clara, 33, understands the occasional word. Three-year-old German and Aida, 16 months, perk up when they hear "bye-bye" and other commonly used terms. But after six years in the U.S. living in one of the city's urban barrios, Spanish is the dominant language spoken inside and outside their home.

"I want to learn English. I know it would help me get ahead. But I have to work 65 hours a week to raise my children and pay my bills. That has to come first before anything," says Espino.

He has plenty of company.

Fewer than half of the Houston residents who speak one of the city's top three non-English languages consider themselves fluent in English, according to recent census figures. The languages, unsurprisingly, are Spanish, Vietnamese and Chinese.

The percentages are about the same nationwide for the same three languages.

English fluency is a hot-button issue in the national immigration debate, as advocates of tighter restrictions contend immigrants threaten the nation's English-speaking identity.

In late April, President Bush told reporters that he thought the national anthem, The Star-Spangled Banner, should only be sung and recorded in English. Later, as the U.S. Senate grappled with its immigration bill, members added two amendments: one declaring English the national language and another recognizing it as the country's "common and unifying tongue."

The amendments were immediately denounced by opponents as racist or anti-Hispanic.

But advocates of more restrictive immigration policies believe many immigrants prefer transplanting their old culture to assimilating into their new one. They suggest this may be especially true among Latin Americans immigrating to places such as Texas that once were part of Spain or Mexico.

"The United States has no historic precedent of large numbers of people coming to this country who could argue that they were returning to a country that was once theirs," the Federation for American Immigration Reform (FAIR) says on its Web site.

Houston immigrants, however, say their lack of fluency in the national language impedes their economic success, hinders daily activities, leaves them open to exploitation and, top on their list, could hurt the future welfare of their children.

"Many immigrants don't speak English, but it's not because they are lazy or don't want to learn it or want to make everyone else speak Spanish or Vietnamese. They just have other priorities like providing for their basic needs," says Nelson Reyes, executive director of the Gulfton Area Neighborhood Organization.

Reyes, who emigrated from war-torn El Salvador in 1990 at age 16, started to learn English in Houston schools after two years of removing asbestos from structures in Washington, D.C.

"I always had it in my mind that I needed to speak the language," Reyes said, though he acknowledged it's possible to get by without English in parts of Houston.

"It can be like living in our native countries. You can live your life here without speaking English because the business sector is offering everything you need to survive."

Jumping in

On most days at the Chinese Community Center on Town Park in the heart of southwest Houston's "Asia Town," the halls ring with the sound of new and longtime immigrants diligently and noisily trying to learn English. Several levels of literacy and English as a second language classes are conducted daily and, invariably, are packed.

"Eighty percent of our students have college degrees. The other 20 percent are their family members who emigrated with them," says adult education coordinator Anita Lin.

"Their only drawback is that they don't know English and that's like a basic in this country. Without that, they can't go anywhere."

On the second day of the latest "zero level" class, newcomers to the U.S. of all ages were learning to count to 100, chanting out their number in turn. When they finished, they gave themselves an enthusiastic round of applause. In another class, more advanced students were following the saga of a couple whose slow courtship was being taught in English for later quizzing.

"Since I have moved to the U.S., I have to learn English to survive and establish myself in my new land," says Lichen Chiu, 45, speaking through a translator. Chiu emigrated from Taiwan less than two months ago and is taking the class with her 18-year-old daughter, Joyce, while her husband works as a handyman.

In the evening, they try to teach him what they have learned in class as they review their lessons.

Ly Kim, 60, one of the oldest people in the class, is determined to learn English after 16 years in the U.S.

"When I got here, I had seven grandchildren I had to take care of and had no time to take classes or study. Now they're grown up and gone. It's my turn," says Kim.

In his 2004 book, Who Are We? The Challenges to America's National Identity, Harvard professor Samuel Huntington fueled the English-only movement by asserting that large-scale immigration by people speaking a common language gives them less reason to assimilate than their European predecessors .

But a recently published survey by Ruben Rumbaut and Frank Bean, sociologists at the University of California, Irvine, and Douglas Massey, a sociologist at Princeton University's Woodrow Wilson School, concluded English never has been threatened seriously as the dominant language in America nor is it today.

"Their study confirms what we already know. The second generation invariably becomes English-competent, and even the first generation eventually does as well," says Nestor Rodriguez, chairman of the University of Houston sociology department.

'It just takes time'

In Napoleon Square Apartments, an 800-unit immigrant village that is home to the Espinos and other families from Latin America, Spanish prevails. But even here, in a teeming heart of immigrant Houston, one apartment rang recently with the sound of the Spanish-speaking enthusiastically trying to learn English.

Even Start, a Neighborhood Centers Inc. project, is an onsite interactive English literacy program that teaches mothers and their children together. They then return home and teach the fathers. On this day, they were learning forms, colors, numbers and shapes.

"I wanted to learn but I just didn't know where I could go. The classes are too expensive for me. Then I found about these classes and they're free, and so here I am," said Maricela Ortega, the mother of two and a Houston resident for seven years.

Clara Espino and her two youngest children are fellow students along with her sister, Zoila Garcia. After the recent class, they used brightly colored, plastic place mats adorned on one side with the alphabet and on the other with English activity games.

They're an investment in hope

"Someday, we're all going to be sitting here speaking English," Clara Espino said. "My eldest son already knows how. It just takes time."