Nearly half of Los Angeles County's immigrants here illegally lack a high school diploma, and 60% do not speak English well, according to a study.
Nonprofits and foundations must work with the public sector to make sure there are enough English classes in the event of a mass legalization, said Maria Blanco, vice president of civic engagement at the California Community Foundation, which partially funded the paper released Tuesday by USC.
If newly legalized immigrants do not learn English, their job prospects are likely to remain limited.
"If we just do legalization but we don't do English language education, we'll really have to wait another generation," Blanco said.
As the debate over immigration reform gets underway in Washington, the stakes for California are particularly high.
One in four of the estimated 11 million people thought to be in the United States without legal authorization lives in California. Statewide, the USC study estimates that about 7% of residents, or more than 2.6 million people, are in the country illegally.
In Los Angeles County, 63% of immigrants here illegally are from Mexico and 22% from Central America, according to the study. Eight percent are from the Philippines, Korea or China.
In some parts of Koreatown and South Los Angeles, one in three adult residents is in the country illegally, according to the study.
Countywide, about one in 10 adults is an immigrant who crossed the border illegally or overstayed a visa, the study found. Many of those immigrants have put down roots here: Half have been in the country for more than a decade, and 12% are homeowners.
Many are also the parents of American citizens. In Los Angeles County, one in five children has a parent living in the country illegally, according to the study.
"The share of children with at least one undocumented parent really speaks to the interwoven generations," said Manuel Pastor, director of the USC Center for the Study of Immigrant Integration and a coauthor of the research along with Enrico Marcelli of San Diego State University. "Another thing that's striking to me is the length of settlement of the undocumented population. Rather than the person who stands in front of Home Depot who just got here a year ago, it's actually a more settled population."
Immigrants residing in L.A. County illegally have a median income of $18,000 a year, compared with $47,000 for U.S.-born residents. Half work in factories, restaurants, construction or house cleaning, the study found. Only 33% have health insurance.
The study's authors expect the earnings of unauthorized immigrants to increase if they receive legal status and can more easily switch jobs. By a conservative estimate, newly legalized immigrants in L.A. County could collectively earn an additional $1.5 billion annually, according to the study. Statewide, the income gain could be $4.6 billion annually.
Opponents of legalization have countered with studies showing that immigrants could use trillions of dollars in government benefits in the coming decades.