ST. PAUL — Do you sing better when the song is written about you?

Leah Haliburton thinks so.

She belted out the final chorus of a song called “Triunfare,” which means “I will triumph” in Spanish. The song was written especially for her Park High School class in Cottage Grove, which gave it extra meaning for her.

“Usually when we sing, we spend so much time trying to interpret what the composer means,” Haliburton, 17, said. “Well, here we actually have the composer, and he can just say, ‘No, I mean this!’“

She nodded toward the star of the classroom, Julio Morales, who was perched at the piano.

Morales and Jean Angelus Pichardo are Mexican composers who have written music for Minnesota choir classes.

They are visiting the schools to help with practice and will visit again for the world premieres of their works in a concert in May.

They have written six original pieces for seven choirs, working with students in St. Paul, Minneapolis, Blaine, Richfield and Cottage Grove.

The composer-exchange program is sponsored by the Minneapolis choral group VocalEssence. Called “!Cantare!” (“I will sing!”), it annually brings Mexican composers to Minnesota — who expose students to their culture as well as their music.

Morales is a music professor at the University of Veracruz in Mexico, and a prolific composer. He visited Park High School in October, wrote the original choral music, then mailed the scores to music teacher Ben O’Connor so the students could practice it.

On a recent Friday, Morales taught a class of 34 juniors and seniors in the school’s Concert Choir.

He started with a series of warmups — which were comical.

“Say no,” he said — and the students shook their heads to stretch their neck muscles.

“Say yes,” he said — and the room nodded.

As they sang random warmup notes, two girls launched into a rehearsed dance step, while others snapped their fingers. One girl stretched out her arms theatrically, begging the boys to sing louder.

Morales sat at the piano, laughing, as teacher O’Connor conducted.

They polished the choral piece, line by line, as Morales listened intently.

The whole class, he said, flubbed the pronunciation of Spanish words. Morales said the consonants sounded crisp at the beginning of the song, but fatigue set in by the end.

O’Connor agreed. “Work with your mouths and tongues and lips. Don’t get lazy as the song goes on,” he said.

Afterward, Morales answered questions from the class.

What is his inspiration for their song?

“I see in you a lot of energy and expectations for the future,” he said.

Any surprises about American life?

He said most Mexicans learn about the U.S. through TV. But he looked around the room in mock surprise: “There are no dinosaurs here! No fighting!”

One girl gushed: “Have you been to Chipotle? It’s my favorite!”

Morales made a face. “It’s not real Mexican food,” he said.

He asked the class why American coins don’t have numbers showing what they are worth — 1 cent, 5, 10 or 25 cents.

At the end, he was asked: What’s his favorite music to play?

“Looking at music that is not jazz and making it jazz,” he said.

To demonstrate, he plunked out the simple melody of “Twinkle, Twinkle, Little Star.” He began to apply flourishes in improvised layers of sound, until it miraculously blossomed into a minor jazz masterpiece.

The class gasped, then burst into applause.

“He is such a blast!” said student Haliburton.