No language trade-off: Bilingual children reliably acquire English by age 5
In the United States, more than 12 million children hear a minority language at home from birth. More than two-thirds hear English as well, and they reach school age with varying levels of proficiency in two languages. Parents and teachers often worry that acquiring Spanish will interfere with children's acquisition of English.
A first-of-its-kind study in U.S.-born children from Spanish-speaking families led by researchers at Florida Atlantic University finds that minority language exposure does not threaten the acquisition of English by children in the U.S. and that there is no trade-off between English and Spanish. Rather, children reliably acquire English, and their total language knowledge is greater to the degree that they also acquire Spanish.
Results of the study, published in the journal Child Development, show that children with the most balanced bilingualism were those who heard the most Spanish at home and who had parents with high levels of education in Spanish.
Importantly, these children did not have lower English skills than the English-dominant children. Children's level of English knowledge was independent of their level of Spanish knowledge. U.S.-born children who live in Spanish-speaking homes and who also are exposed to English from infancy tend to become English dominant by age 5—but some more so than others.
The study, conducted in collaboration with The George Washington University, is the first to describe the outcome of early dual language exposure in terms of bilingual skill profiles that reflect the relations in the data between children's skill levels in their two languages. The study addresses the question of what level of English and Spanish skill can be expected in 5-year-old children who come from Spanish-speaking homes in which they also hear English in varying amounts.
"We found that early in development, children who hear two languages take a little longer to acquire each language than children who hear only one language; however, there is no evidence that learning two languages is too difficult for children," said Erika Hoff, Ph.D., lead author and a professor in the Department of Psychology within FAU's Charles E. Schmidt College of Science on the FAU Broward Campuses.
A key finding from the study is that low levels of proficiency in two languages at age 5 is not a typical outcome of exposure to two languages. Bilingual children who have weak skills in both languages at age 5 may have an underlying impairment or inadequate environmental support for language acquisition.
For the study, Hoff and co-authors Michelle K. Tulloch, a Ph.D. student in the Charles E. Schmidt College of Science; and Cynthia Core, Ph.D., an associate professor in the Department of Speech, Language and Hearing Sciences within the Columbian College of Arts and Sciences, The George Washington University, used an examiner-administered test to measure the English and Spanish expressive vocabulary of 126 U.S.-born 5 year olds from Spanish-speaking families with one or two immigrant parents who have been exposed to Spanish since birth and who have also heard English at home in varying amounts, either from birth or soon thereafter. They also measured indicators of the children's language learning ability.
Prior to this study, differences among bilingual children were described primarily in terms of dominance (English-dominant bilinguals, Spanish-dominant bilinguals) and balance, but that turns out not to be the only way in which bilinguals differ.
"Previous research has tended to treat bilingual children's development in each language as a separate outcome, rather than treating dual language skills as the single outcome of dual language exposure," said Hoff. "This approach not only fails to adequately capture the nature of children's dual language skills, it also leaves unaddressed the question of how the acquisition of one language is related to the acquisition of another."
Findings from this study suggest that dominance is not the same thing as proficiency. Bilinguals differ both in dominance and in total language knowledge. Teachers and clinicians cannot infer a bilingual child's language proficiency from that child's language dominance. There are balanced bilinguals at age 5 who have stronger English skills than some English-dominant bilinguals. Individual differences in dominance are significantly related to home exposure, although the function that relates exposure to dominance is biased toward English.
Balanced language exposure at home does not result in balanced proficiency; Spanish-dominant home exposure appears to be necessary. Individual differences in total language knowledge are significantly related to indicators of language-learning ability, measured in this study in terms of phonological memory and nonverbal intelligence.