She said the United States is one of the few nations to consider children who infuse words from their native language into the English language they are learning as incompetent in both languages.

That phenomenon, called code-switching, is often used to help children express themselves in a new language, she said, but few are credited for their efforts.

"Dominant-culture kids who code switch are rewarded, but Spanish speakers who do so are called limited in their language," said Escamilla, a professor at the University of Colorado.

The conference was designed to promote using a student's primary language to close the achievement gap and educate those who work with bilingual children about why they speak and write as they do.

Escamilla focused on Spanish speakers because she says while there are 350 languages spoken in the United States, 80 percent of non-English speakers use Spanish.

She said that most children use their native language to process their second language, much like English speakers do when they are learning a new language: they hear the new language, translate it into English in their heads, and then speak the new language back.

While teachers are patient with English-speakers learning a new language, they quickly grow impatient with Spanish-speakers trying to express themselves in English, Escamilla said.

"Kids start using one or two words, and then we say 'Voila,' ” they're fluent, she said.

Escamilla says bilingualism helps students, and that those students who often splice their sentences or thoughts between Spanish and English are actually the most proficient in both languages, instead of the least, as the U.S. education system enforces, she said.

She also worries that forcing children to speak only in English worsens bilingual children's proficiency in their native tongue.

A study of Puerto Rican children in Chicago tested the children when they were 4 and again when they were 7. In those three years, the children went from normally developing language skills in Spanish to language delayed.

"It wasn't a problem at home. It was at school. When children start speaking their new language, everyone is happy, but they have hurt their first language use," she said.

Many children who begin speaking English only at school lose their speaking ability in their native language. They have listening comprehension, but often cannot respond.

"By 7 these kids couldn't do what they could when they were 4 years old," Escamilla said.

While Escamilla realizes that schools will continue to be predominantly monolingual, she encourages parents to speak only their native language at home, and make their children speak back to them in their native language.

"I fought with my kids on it. When they were 13, they didn't want to do it anymore. But now that they're in their 20s, they are thanking me," she said.

smcfarland@sltrib.com