Julia is a young Dominican girl who moves back to the United States at age ten. Possessing a deep love for language and aspiring to become a writer, she pays close attention to the ways her names shape her identity. Throughout her adolescence, she balances a desperate urge to assimilate with her American classmates against her profound ties to her Spanish-speaking family and heritage.

Mauricia is the eldest sister in the Alvarez family, born in New York before her parents briefly returned to the Dominican Republic. Because her name honors her grandmothers Mauran and Felicia, it carries deep family history but proves difficult for English speakers to pronounce. She frequently endures incorrect variations of her name like "Moor-ee-sha" and "Maudy," which complicates her experience in American society.

Ana is the youngest sister in the Alvarez family. With blond hair, pale skin, and a short name that translates smoothly into English, she physically resembles the American ideal more than her sisters do. Despite her Anglo-American appearance, she still receives affectionate Hispanic nicknames like "Anita" from her boyfriends, showing that her identity is subject to the perceptions of others.

Julia is the mother of the Alvarez sisters and shares her first name with the protagonist. She is eager for her family to blend into American society and actively encourages her children to embrace their new English nicknames. Her desire to assimilate sometimes borders on shame regarding her heritage, such as when she pretends her infant daughter Mauricia is named "Maureen" to fit in with other mothers at the hospital.

Papi is the patriarch of the Alvarez family who moves his wife and daughters from the Dominican Republic to New York City. He provides for his family in a new country while maintaining his Dominican roots. He shows immense pride in his daughters' accomplishments, celebrating their milestones and supporting their ambitions.

Tía Josefina is Julia's aunt, a vibrant member of the large extended Dominican family. She attends school functions in large groups, speaking rapid, rhyming Spanish and demonstrating the profound familial support system that surrounds the Alvarez sisters.

Aida Margarita is a raised daughter within the extended Alvarez family. She accompanies Tía Josefina to school events, contributing to the large, joyful crowd of relatives that reminds Julia of her rich cultural background.

Tía Amelia is Julia's aunt and godmother. She is a cheerful presence at family events, sitting in the front row and conversing warmly in Spanish, representing the undeniable presence of the family's Dominican heritage.

Tía Pilar is an aunt within the Alvarez family network. Like the rest of the extended relatives, she shows up to support her nieces with loud, joyful conversation in Spanish, cementing the family's strong cultural presence in an otherwise American setting.