A procession of American Indians marched through Sunset Park, Brooklyn, on a weekend afternoon in early May, bouncing to a tribal beat. They dressed in a burst of colors, wore tall headdresses and danced in circles, as custom dictated, along a short stretch of the park.

But there was something different about this tribe, the Tlaxcala, and when the music ceased and the chatter resumed, the difference became clear: They spoke exclusively Spanish.

The event was Carnaval, an annual tradition celebrated by tribes indigenous to land that is now Mexico. And despite centuries of Spanish influence, the participants identify themselves by their indigenous heritage more than any other ethnicity.

When Fernando Meza is asked about his identity, “I tell them that I am Indian,” said Mr. Meza, a parade participant from the Tlaxcala tribe. “They say, ‘But you’re Mexican.’ And I say, ‘But I’m Indian.’ ”