Twenty-month-old Diego Vallarroel, who looks remarkably like the Nickelodeon character of the same first name, picked up a brightly colored block with the number 2 on it.

He toddled over to his teacher, Katsura Peterson, and proclaimed, "Ni!"

Then he wobbled over to his smiling mother, sitting on a miniature chair, and said, "Dos!"

Welcome to Little Ambassadors, a school teaching keiki ages newborn and up a world's worth of languages.

The national trend of teaching second and even third languages to babies and toddlers has made its way to our shores. Other schools and preschool programs aim to give children a heads up on foreign languages, perhaps before they're even able to say their own name.

Say what you will about academia for the infant set, there are no grade books or desks in this classroom.

"Here at Little Ambassadors we teach through natural play," said founder Kimberly Funasaki, who started the school in September and now has 80 to 100 students enrolled, all under the age of 7.

"Children learn English through play and we are doing the same thing with foreign languages. They are able to absorb the language without being stressed to learn it."

What does natural play look like?

At the Kaka'ako classroom, the colorful walls are covered with pictures from different cultures. A poster of Japanese characters hung low for children to view.

As class began, children removed their shoes and sat on the carpet, squirming in their pants.

Diego's face lit up when Sensei Peterson made puppets dance to "Old MacDonald" in Japanese. Then, while "Who's Behind Me" was read, he listened contently.

During the 45-minute class, Diego's mother, Karina Vallarroel of Kahala, sat in the corner, watching proudly as Diego took interest.

At home, Diego speaks only Spanish, she explained. He is picking up a few words of English and learning Japanese in his weekly classes, Vallarroel added.

Peterson moved quickly from one activity to another, from stacking blocks to Mr. Potato Head, maintaining an energetic lilt in her voice, her patience never wavering. She was quick to get down on hands and knees to play at eye level with her students.

At one point, Peterson flipped through a set of animal flash cards. She hopped up and began singing "Head, Shoulders, Knees and Toes" in Japanese, the children mimicking her movements.

Peterson, who grew up speaking Japanese, said she believes the best way to learn another language is through music.

"I learned English by listening to songs. They help children learn phrases and words," she said.

There is academic play and then there is just play. At times, class looked a lot more like recess — children lost interest in activities and wandered off to play something else. Instead of running around with the rest to catch bubbles, Diego lay on the floor, his sock feet swaying in the air.

Peterson said even this type of behavior is important.

"Just because they are not participating in the activity, they are still listening and learning the language," Peterson said.

How reasonable is it to assume language classes might turn your child into a foreign diplomat?

Vallarroel recalled first telling her friends that she was taking her tot to language classes.

"They thought I was crazy," she said.

And some say there's questions about the effectiveness of such classes, too.

"Generally programs have not been real effective to develop a child's language skills," said Kathryn Davis, director of the Center of Second Language Research at the University of Hawai'i-Manoa.

Davis said she believes it is important for children to learn a second language, but there has to be a purpose for it. Taking a tot to class once per week is not going to make a child fluent in another language, she said.

Things to consider, she said: Does a child have resources outside of class for further exposure to the language? When a child has a reason to use the skills outside of class, the child will be more receptive to using them, she said.

But Funasaki sees a number of cognitive and academic benefits to learning another language — especially if done correctly.

"If you're just coming once a week, and it's just another extracurricular, then (children) probably are not going to learn," Funasaki said, adding that they encourage parents to learn alongside the child and send home a language CD for practicing.

"It's just like watching a TV show," she said. "You don't just sit your child in front of the TV; you watch with them and reinforce (what they're learning)."

And it isn't about learning every last conjugated verb, she said.

"Our mission isn't to promote fluency, but to make language learning fun for the children and to introduce them to the native sounds of the language," she said. Establishing a good background early helps learning later, she said.

Diego's mom admits hoping one day he'll be fluent in more than one language for academic and business opportunities.

Will he? Time will tell. But for now, back in the classroom, Sensei Peterson has pulled out the puppets to sing the goodbye song.

"Sayonara!" sang Peterson.

"Sayonara!" Diego sang back.