One said he was a neighbor of Steve Jobs. Others go home to the trailer park off El Camino Real.
In Jacobs' class, they bond over their status as newcomers and the fact that they're all "English language learners."
Their families were attracted to Palo Alto by its reputation for great schools a reputation that's becoming global.
Fully one-third of Palo Alto's 12,300 public school students report that they speak a language other than English at home.
Mandarin is predominant, followed by Spanish, Korean, Hebrew and Russian. Many of those students are fully bilingual in English as well.
But a subset about 1,400 are considered "English language learners," a designation based on results of a language test they take upon arrival here. So-called "E.L.L. students" are singled out for special instruction until their English is deemed adequate for them to participate in regular classrooms.
Among English-language learners, the top home language is Spanish, followed closely by Mandarin. Further down on the list are Korean, Japanese, Russian and Hebrew.
In elementary grades, English learners stay in mainstream classrooms and receive special in-class assistance from tutors who speak their primary language.
But English learners who arrive in middle school or high school are placed in special classrooms such as that of Mr. Jacobs for English and social studies. In that setting, a full range of "primary-language tutors" are available to help them in any subject.
In the shadow of Stanford University, schools in Palo Alto historically have drawn a fair share of international students.
More recently, the rise of Silicon Valley and the Internet have magnified the attraction.
Close to half of Santa Clara County households 49.6 percent reported that they "sometimes or always spoke a language other than English at home," according to the 2010 U.S. Census. The Los Altos School District says 30.4 percent of its current students report a primary home language other than English.
The percentages appear to be up, at least slightly, from a decade ago. The Palo Alto school district's "Home Language Survey" of 2000-01 indicated that about 25.6 percent of students spoke a primary language other than English. Like today, Mandarin was predominant, followed by Spanish, Korean, Russian and Hebrew.
Students land in Palo Alto because of a parent's job with a technology company or appointment at Stanford.
Others with means have searched around and chosen to move to Palo Alto because of its reputation.
"They find out about Gunn through education consultants especially in Asia that put their finger on Palo Alto," Jacobs said.
"We also get special-needs students because parents identify Palo Alto as a district that takes really good care of students with special needs.
"People are really good at using Google these days."
One student from Asia reported that his family first moved to New York but didn't like the weather.
"Then we searched and we asked friends. They all said Palo Alto is the best place near Stanford so we decided to live here," the student said.
Another student, injured by a truck while playing street soccer in Mexico, arrived here in a wheelchair some years ago and graduated from the program, Jacobs said.
"If we're so happy to have all these wealthy Asians and Europeans coming, then why shouldn't we be happy to have the lower-income people who are washing dishes and cleaning houses?" he said.
"Americans are irritated and bothered by it. They think they're automatically illegals, but they aren't, necessarily. Why shouldn't they have the same opportunities as the rich folks that have come in and bought a $5 million home in Palo Alto?"
Some students, who were born here but whose parents have moved to Mexico, return here for schooling and live with relatives.
But Jacobs, who has taught English as a Second Language (ESL) for nearly 40 years, 20 of them at Gunn, said, "Every ESL program has some illegals."
Students sometimes will share that information once they've developed a trust with teachers that they won't be turned in, he said.
The U.S. Supreme Court in 1982 invalidated a Texas law denying education funding for illegal immigrant children and also struck down a school district's attempt to charge tuition for undocumented students.
The National School Boards Association relied on that case in a 2009 publication sent to every school district in the United States summarizing legal issues surrounding the education of undocumented students. In general, the publication favors providing those students an education.
It advises school districts not to question students about their immigration status and not to report such information, if known, to federal immigration authorities.
The Palo Alto school district has no official policy on undocumented students but follows a circular from the U.S. Department of Education advising that districts may not adopt policies that discourage students from participation.
Though most teen English learners in Palo Alto live with their families, some are living largely on their own in apartments that have been rented by their parents.
"Some kids live with very little supervision, and other kids live with parents who are controlling every minute of the day," Jacobs said.
In all cases, "I encourage parents to let them function as American students let them go to school dances, football games, baseball games, homecoming activities, join clubs," he said.
"You want to expose them to as much as you can."
Each year a handful of kids turn up at Gunn with no English at all and are placed with Jacobs' assistant, Kira Levina, for small-group instruction.
This year, Levina is working with a student from Spain and another from China.
"We start with the alphabet," Levina said.
"When they come they sometimes miss their country, and their parents in some situations, so it's sometimes very emotional for them," she said.
"This is when it's challenging to teach them and to make them feel comfortable. It's very important for them to feel comfortable because we want them to be happy. That helps them learn English better."
For students who aren't rank beginners, Jacobs said he still starts with something basic: Gunn's student handbook.
He explains to them how to find a computer at school, how to sign up for a sports team or what to do if they feel sick in class.
They talk about the American concepts that may seem new and strange sexual harassment and bullying.
They learn about grade point averages, SAT tests and how to get help from Gunn's College and Career Center.
"They're all here for the educational opportunities," Jacobs said.
"Either there's very little opportunity where they came from, or the competition is so rough that their parents brought them here that would be China, Japan and Korea. They don't have a community college system for kids that don't have top GPAs."
In other home countries, money is a barrier.
For students with hustle, the United States still looks very much like a land of opportunity.
Moscow-born Henry Matevosyan, who speaks Ukrainian, Russian and Armenian, came here in 2009 after his mother, a software developer, won a green-card lottery.
In Russia, Matevosyan said, there are cost barriers that prevent students like him from pursuing their fields of choice.
"Here, you can get wherever you want you just have to study for it," he said.
Besides his coursework at Gunn, Matevosyan works 20 hours a week at McDonald's, making burgers, staffing the register, sometimes even helping with the computers.
"I'm going to be next month manager," he said with pride.
The Gunn junior who also works at computer programming on the side aspires to follow in his older brother's footsteps by attending Foothill College and then transferring to the University of California.
He likes biology and math, soccer and tennis, and hopes to pursue a career in computers.
"I played last year tennis and soccer for Gunn, but this year I don't have time I'm very busy," he said.