As class president of her high school in Los Angeles, Daniella Martinez Cerezo opened her graduation speech on Monday evening by thanking all the immigrant parents in the audience.

“We know your journey hasn’t been easy — the fear, the long hours, the sacrifices no one sees,” she said. “This diploma isn’t just ours. It’s yours, too. Every step we’ve taken was made possible by the path you walked before us.”

Then, switching from English to Spanish, Ms. Cerezo addressed two parents who weren’t there.

Her own.

“Hello, Mom; hello, Dad,” she said, her voice cracking with emotion. “I know you couldn’t be here today because you’re afraid. I don’t know how to live my life in a world without you both. I don’t say this a lot, but thank you. Thank you for giving me life.”

Her parents, like many immigrant Angelenos who are undocumented, are avoiding public places while immigration agents roam the city.

As unrest erupted in Los Angeles over federal immigration raids, students across the city’s public schools, where nearly three-fourths of the student population is Latino, were preparing to collect their diplomas and celebrate with friends and family.