Many of the parents work several jobs to get by, as Mr. Gonzales’s mother did, and some students miss weekend rehearsals to work in the fields, supplementing family income. The cost of costumes — which can run up to $300 — and special shoes can be prohibitive. Fund-raisers have become folklórico fixtures, with troupes performing at church fiestas, weddings and even casinos to raise money for stock costumes, and parents selling tamales and T-shirts outside packed auditoriums.

Sometimes teachers pick up the slack. Among them is Gustavo Sandoval, a science teacher in Thermal, Calif., where 90 percent of high school students live in poverty, many in ramshackle mobile home parks. Mr. Sandoval and his wife, Gabriela, who works in a school kitchen, subsidize an after-school folklórico program at Desert Mirage High School out of their own pockets — about $11,000 a year. “We want to give our youth something positive to do,” he said.

In Porterville, Mr. Gonzales “made a decision to give it my all,” he said, by using his own seed money to jump-start the program 15 years ago. His sister, Irma Rios, continues to sew many of the costumes.

The principal of Porterville High, Jose Valdez, said that when he’s having a bad day he wanders into Mr. Gonzales’s rehearsals, where the effervescence and joy lifts his spirits. “It gives the students a reason to come to school,” he said. “They’re all in. They perfect their dances for him,” he said of Mr. Gonzales, “because they see and feel his love for what he does.”

At the Show Offs, a group of female folkloristas from Porterville performed “La Bruja”(“The Witch”), a dance from Veracruz in which women in gossamer white dresses emerge onstage, a glass containing a lit candle balanced atop each of their heads.

The ethereal glow suggested the transformative power of folklórico. As Mr. Goyal from Central High, put it: “Even though we stomp really hard, we feel light.”