MUKILTEO — By day, she’s a CPA, poring through audits.

At night, she’s a booty-shaking Zumba teacher in colorful Spandex.

On the gym floor, Nancy Isely is hard to miss, that’s for sure. And for students who speak little or no English, it’s easy to follow her spins, swivels and sambas in a new class, Zumba en Espanol.

It is the first exercise class in Spanish at the Mukilteo YMCA.

Zumba is a pulsating workout rooted in Latin American dance and music, but instruction is in English in the 15 or so other classes at this YMCA.

Isely, 58, a Brier accountant and longtime fitness instructor at area Y’s, started teaching the Spanish Zumba class in February.

“It is easier when people can get it in their own language and I think they have more fun,” said Isely, who is bilingual.

“I grew up dancing and going to Mexican dances. Dancing is popular in the Mexican culture. Community is very important. The women do stuff together and they do it word of mouth. They gravitate to each other.”

Now the women gyrate together.

“Latino men won’t go to any classes,” Isely said. “I invite them and they just laugh. If you ever see the classes in Mexico, there aren’t men in the class.”

Her playlist includes “La Vida Es Un Carnaval” by Celia Cruz, “Rompe” by Daddy Yankee, “Adiós” by Ricky Martin, “Salomé” by Chayanne and songs by Santana.

The weekly class was an instant hit.

“The first day I had 15 people,” Isely said, “and the next week I had 25 people.”

There are plans to add a second Zumba en Espanol class, said Kate Rossart, Mukilteo program director.

This is a way to reach out to Hispanic families at the Y’s Casino Road center in Everett, which has education classes and other resources but not fitness programs.

“It is one of the ways we are trying to be inclusive with that group of folks,” Rossart said. “It’s in their own language and they can ask questions. The instructor talks about the technical aspects of working out.”

Yes, there are technical aspects to Zumba, which to the untrained eye might appear more burlesque show than Y studio.

“We talk about the technique, and what muscles they are stretching,” Isely said. “When I explain that need to have the right shoes, the light bulb goes off: ‘Oh, so that’s why my knees are killing me.’”

Lucia Margarito of Lake Stevens said through a translator that she likes having the steps explained and verbal cues that she can understand so she isn’t just chasing the instructor around. Margarito’s daughter attends another program at the Y while she Zumbas with her friends for an hour in the gym.

English is a second language for Isabel Madsen, but she has lived in Mukilteo long enough to speak it fluently.

She likes the camaraderie of Isely’s class.

“With the Latin people, we’re born with music inside us. I wanted to experience it with my ladies, my people,” she said.

The class is open to people of all languages.

Linda Xu is Chinese.

“She has a lot of dance flair,” Xu said of Isely. “All I heard was music, good music. And she has nice posture.”

The YMCA offers special rate membership prices based on income. Zumba en Espanol is 7:15 p.m. Monday.

Andrea Brown: 425-339-3443; abrown@heraldnet .com. Twitter: @reporterbrown.