English Language Learner versus Language Learner

Is there really a cognitive advantage in being a bilingual? A recent review of published papers by Angela de Bruin, Barbara Treccani, and Sergio Della Sala in the journal Psychological Science reveals a publication bias favoring only those that report a positive correlation between bilingualism and executive control. In the review, de Bruin and coauthors write, "Our overview shows that there is a distorted image of the actual study outcomes on bilingualism, with researchers (and media) believing that the positive effect of bilingualism on nonlinguistic cognitive processes is strong and unchallenged."

I am a bilingual and I think it is a worthwhile endeavor to become one. Becoming proficient and conversant with two languages is truly a rewarding accomplishment. Becoming a bilingual, unfortunately, is not just a matter of wanting to become one. Cognitive abilities in one language are expected to influence progress in a second language. Not taking into account the quality of instruction and exposure can easily impede a child's progress in both languages.

A recent paper published in the Journal of Educational Psychology looks at how the language used at home affects a child's proficiency in two languages. Kijoo Cha and Claude Goldenberg of Stanford University report that there is indeed a relationship between a child's proficiency in two languages. A child who is proficient in Spanish is more likely to be proficient in English as well, but the relationship is moderated by what happens inside a child's home. The following figure, for instance, shows how complex these relationships really are.
Above copied from
Cha, K., & Goldenberg, C. (2015, April 20). The Complex Relationship Between Bilingual Home Language Input and Kindergarten Children’s Spanish and English Oral Proficiencies. Journal of Educational Psychology. Advance online publication. http://dx.doi.org/10.1037/edu0000030
The graph slightly differs from what is published. It has been colorized so that it is easier to see the different lines.The different lines correspond to different levels of oral proficiency in English. The blue line are for students who are deemed well above average in English while the red line are for those who are well below average. There is clearly a difference in slopes between these lines. The slope essentially describes how proficiency in Spanish correlates with what language is spoken at home. The red line which corresponds to students struggling in English is flat. It is quite informative to see that for these students, the amount of Spanish spoken at home does not greatly affect proficiency in Spanish. On the other hand, the blue line which corresponds to students doing well in English is quite steep, demonstrating that with this set of students, oral proficiency in Spanish is strongly correlated with how much Spanish is spoken at home.

An opposite trend is seen when oral proficiency in English (instead of Spanish) is plotted against the language spoken at home and students are grouped as separate lines, this time, according to their proficiency in Spanish. The line that turns out to have the least slope corresponds to students who are well above average in Spanish. The English proficiency of children who are orally fluent in Spanish seems less correlated with the amount of Spanish/English spoken at home.

This study shows that it is important to consider where children are in their language learning. In order for children to grow in their mother tongue, one must take into account not just use of the language, but how the language is used. How cognitive abilities are emerging in the child with the use of the mother tongue needs consideration as deficiency in either language points to a higher likelihood of deficiency in both.