English and Spanish alternate seamlessly in the classrooms at the Mission Education Center in San Francisco. Decorative signs identify objects that in other schools would seem too basic to name: "clock" and "door."
This public elementary school has for 40 years served children who have just arrived from Latin America and speak only Spanish, who beyond its walls are out of their element in almost every way.
Those students are dramatically fewer now. As the flow of immigrants from Mexico has dwindled in recent years, the school's enrollment has plummeted from a high of 264 students in the mid-2000s to 72 this past spring.
"We had low enrollment in 1994, when Prop. 187 passed," said fifth-grade teacher Lilly Chow, referring to the controversial ballot measure that sought to halt public services to unauthorized immigrants and was struck down in U.S. district court. "But never like this."
The change has transformed the size and cultural makeup of the school's classes. It has sliced the number of teachers nearly in half. And it has the small, close-knit staff deeply worried about whether the school will survive and how its young, vulnerable students will fare if it doesn't.
Students normally stay for a year or two, learning English and catching up on academics before they plunge into a conventional school.
Many of those children arrive in the U.S. culturally overwhelmed and academically far below their grade level. In a classroom full of English speakers, without specially geared instruction and care, Chow fears, "Eventually they're going to be dropouts."
At Mission Education Center, a yellow schoolhouse amid the Edwardian homes and quiet slopes of San Francisco's Noe Valley neighborhood, students learn academic subjects like math and science in Spanish and study English for an hour a day. Parents sign a waiver exempting their children from Proposition 227, the 1998 measure that required all public school instruction be done in English.
Classrooms that just a few years ago brimmed with children now host only 12 to 14 students per grade. Some rooms are entirely dark, used only for after-school programs.
On a recent Thursday, teaching coach Rosie Esparza gave five fifth-graders with intermediate English an intensive lesson based on the solar system.
"What's another word they give for moons?" she asked.
"Satellites," the children echoed back. Only one in the group was Mexican. Others hailed from El Salvador and Nicaragua.
Since its founding, this little school has regularly seen the evidence of large international changes. A flood of children from El Salvador - among them Ricardo Cortez, now the school's fourth-grade teacher - arrived as civil war ripped the country in the 1980s. A wave of Hondurans appeared, then ebbed, after Hurricane Mitch in 1998.
Still, Mexican students predominated, delivered to San Francisco by what the Pew Hispanic Center has termed "the largest wave of immigration in history from a single country to the United States." Over the past four decades, the Mexican-born population in the U.S. has surged to about 12 million, many of them here illegally, Pew reports.
It's hard to identify how many of those are students, since Mission Education Center and other California public schools do not inquire about students' immigration status. By law, all children present must be educated.
About five years ago, immigration from Mexico started to drop, and fast. Pew points to a number of explanations: The U.S. economy collapsed while Mexico's had been gradually strengthening. The dangers of rising drug-cartel violence in northern Mexico heightened. U.S. border enforcement and deportations intensified.
"They have more opportunities in their country now, so they're staying," said the school's second-grade teacher, Annie Rodriguez, whose great-grandparents emigrated from Mexico and who learned Spanish only as an adult, in college. "What is there here? They don't see that dream as they did before."
Christina Wong, special assistant to San Francisco Unified School District Superintendent Carlos Garcia, oversees the district's programs for students learning English as a second language. While it's possible that other factors - such as parents choosing different schools for their newcomer kids - could account for part of the enrollment shift, she said, "The immigration pattern is real."
Pew reported in April that with fewer Mexicans coming to the U.S. and more leaving, net immigration from Mexico had "come to a standstill."
The staff at Mission Education Center already knew that.
The school's enrollment from most Latin American countries has waned in the past few years, but the drop from Mexico is especially steep. Mexicans made up nearly half the students in spring 2009; now they are just 15 percent.
From 2009 to 2010 alone, the number of Mexican students plummeted from 89 to 25. Now there are 11.
In contrast, enrollment has held steady at about 150 at the Chinese Education Center, the San Francisco Unified School District's elementary school for Mandarin- and Cantonese-speaking newcomers. At International High School, which also serves newcomers, Chinese students surpassed Latinos to become the majority in the 2010-11 school year.
Children at Mission Education Center come from various circumstances, but many lived in rural towns with limited schooling. Several have spent years separated from their parents who came to the U.S. ahead of them. Once in San Francisco, almost all are low income.
The students' projects on display in the halls include dioramas of their gardens in Latin America, lush with avocado trees and rowdy with dogs and birds. Handwritten letters to their old homes read: "Dear House, When I think of you I feel discouraged. ... I remember when we ate delicious melon together, like brothers, and played hide-and-seek under our beds, lovely and soft."
Mission Education Center's instructors - most of them immigrants or grandchildren of immigrants - teach these children "everything," said Chow, who emigrated from Nicaragua in her thirties on a Fulbright scholarship and has taught at the school for 23 years. "How to dress for the weather. Hygiene. Nutrition. On top of that, we help them to cope with the emotional issues that most of them have."
Lianne Milton for The Bay Citizen Math instructor Ricardo Cortez, who was a former Mission Education student, gives a thumbs up to students.
In that sense, the school's shrinking class sizes help. One Nicaraguan girl in Chow's fifth-grade class was reading at a first-grade level when she arrived last August; by May, she tested at a sixth-grade level.
"It's a paradise for me and my students," said Chow. "Having these low numbers, they can really advance. But it's not good for our program."
Fearing that the school could be closed for low enrollment, Principal Deborah Molof has applied to add a dual-language immersion program teaching English and Spanish to native speakers of both languages. That way, she reasons, the native speakers of both tongues could be models for each other, and the newcomers would still get the support they need. The district is considering her application.
Meanwhile, a teaching staff that once numbered 11 is down to six, and still shrinking.
On a recent afternoon, Rodriguez was throwing out old papers and packing to move to a different school. Mission Education Center will need one less teacher next year, and with seven years of service at the school, Rodriguez has the least seniority.
"It seems like every year another teacher has to leave," she said. "It's my turn."