"I can learn much better now," said Keita, who hails from Mali. "It's so good."
The nearly bankrupt school system could afford to offer virtually no programs this summer. But federal dollars reserved for instruction for English-language learners paid for the West Philadelphia camp and a small number of other programs. (The district also offered federally mandated instruction for special-education students, and "credit recovery" for students who need to make up a few classes to graduate.)
Those enrolled in the West Philadelphia program - and the staff who helped them - say the work is vital.
They operated out of an annex of Monumental Baptist Church at 46th and Locust. There, for more than a month, Jean Marie Kouassi and his tiny staff taught the students, ages 11 through 20, about the slope of a line and about self-confidence. "Don't look up and down when you speak," Kouassi instructed a young woman gently after she failed to make eye contact during a speech to other students. "This is OK back home, but here, when you're talking to someone, look them in the eye. It is not rude - it is important, especially in school, with teachers."
Kouassi, himself an African immigrant, came to the U.S. from Ivory Coast in 1993. He earned degrees at the University of Pennsylvania and now works mostly on economic development and education projects in Philadelphia.
He has enjoyed watching the students learn about nutrition through a vegetable garden they planted, and to become more fluent in English. But he's also thrilled by the strides they made in understanding how to be young people in America.
"The culture - that's the most important part," Kouassi said.
On Friday, they celebrated the conclusion of the program with a barbecue. Many dressed in the bright colors of their home countries.
But Fode Doucara, 11, chose a light green button-down shirt, a serious outfit for a boy who is clearly serious about school. He's entering sixth grade next month, and hopes to attend Penn Alexander, a top city neighborhood school.
"I have improved in math, science, and confidence," said Doucara, who comes from Mali and whose hand was often the first to shoot up when Kouassi asked a question. "If you compared me from last year to now, I am really good."
Cheri Micheau, a manager of multilingual programs for the School District, stopped by Friday to help the students mark their achievements. She was thrilled at the help provided to students from the district's booming African immigrant population, Micheau said.
"Kids have different levels of education, different levels of English - but they're so motivated and they've made such progress," Micheau said. "The kids from Eritrea - they were barely speaking. They weren't looking at anybody. But now, they're the first ones to raise their hands."
Radiatou Diarra, 13, a rising freshman at Science Leadership Academy-Beeber and a native of Burkina Faso, came to the camp with her three brothers.
She feels more sure of herself in social situations now, Diarra said.
"I learned how to talk to people properly," Diarra said.
Her brothers have one complaint about the program, Diarra said - one that sounds like lots of other American students at the end of summer camp.
"They just don't want it to end," she said.