A new Northwestern University study provides the first biological evidence that bilinguals’ rich experience with language “fine-tunes” their auditory nervous system and helps them juggle linguistic input in ways that enhance attention and working memory.

Northwestern bilingualism expert Viorica Marian teamed up with auditory neuroscientist Nina Kraus to investigate how bilingualism affects the brain. In particular, they looked at subcortical auditory regions that are bathed with input from cognitive brain areas.

Kraus has already shown that lifelong music training enhances language processing, and looking at subcortical auditory regions helped to tell that tale. “For our joint study, we asked if bilingualism could also promote experience-dependent changes in the fundamental encoding of sound in the brainstem — an evolutionarily ancient part of the brain,” said Marian, professor of communication sciences.

The answer is a resounding yes, according to the study in the April 30 issue of Proceedings of the National Academy of Sciences. The researchers found the experience of bilingualism changes how the nervous system responds to sound.

“People do crossword puzzles and other activities to keep their minds sharp,” Marian said. “But the advantages we’ve discovered in dual language speakers come automatically simply from knowing and using two languages. It seems that the benefits of bilingualism are particularly powerful and broad, and include attention, inhibition and encoding of sound.”

Co-authored by Kraus, Marian and researchers Jennifer Krizman, Anthony Shook and Erika Skoe, “Bilingualism and the Brain: Subcortical Indices of Enhanced Executive Function” underscores the pervasive impact of bilingualism on brain development.

“Bilingualism serves as enrichment for the brain and has real consequences when it comes to executive function, specifically attention and working memory,” said Kraus, Hugh Knowles Professor at Northwestern’s School of Communication. In future studies, she and Marian will investigate whether these advantages can be achieved by learning a language later in life.

In the study, the researchers recorded the brainstem responses to complex sounds (cABR) in 23 bilingual English-and-Spanish-speaking teenagers and 25 English-only-speaking teens as they heard speech sounds in two conditions.

Under a quiet condition, the groups responded similarly. But against a backdrop of background noise, the bilingual brains were significantly better at encoding the fundamental frequency of speech sounds known to underlie pitch perception and grouping of auditory objects. This enhancement was linked with advantages in auditory attention.

“Through experience-related tuning of attention, the bilingual auditory system becomes highly efficient in automatically processing sound,” Kraus explained.

“Bilinguals are natural jugglers,” said Marian. “The bilingual juggles linguistic input and, it appears, automatically pays greater attention to relevant versus irrelevant sounds. Rather than promoting linguistic confusion, bilingualism promotes improved ‘inhibitory control,’ or the ability to pick out relevant speech sounds and ignore others.”

The study provides biological evidence for system-wide neural plasticity in auditory experts that facilitates a tight coupling of sensory and cognitive functions. “The bilingual’s enhanced experience with sound results in an auditory system that is highly efficient, flexible and focused in its automatic sound processing, especially in challenging or novel listening conditions,” Kraus added.

Join the Conversation


  1. Foreign language for everyone at D65!

    This is why EVERY D65 student should get foreign language instruction at an early age just as Wilmette schools.

    Unfortunately, only a select few students at some not all D65 schools get foreign language instruction through TWI. It's not fair to the rest of the parents and students who don't get foreign language training.

    It's time someone steps up and demands it. I hope there will be D65 candidates for next year's election who use foreign language instruction for all as a platform.

    Since we pay premium property taxes we should get premium education for our kids. 

    1. And while we’re at it, let’s push for more musical education…

      … which has also been shown to have lifelong positive effect on a person's language skills by this same laboratory (and many others).

  2. Bilingual tradeoffs

    TWI is the best way for non-English speakers to learn English.  But at the expense of music, language, and small classrooms for all the rest of the students.  The scores at our magnet schools are embarrassing. 

    Why do we in Evanston keep our heads in the sand about how bad our schools are?  Too many adminstrators and not enough personnel with direct student contact.  Referendums and political agendas keep everyone busy trying to define racism and social justice.  Our children suffer year after year.  NAACP has too much power in the schools.  Their motives are fine and noble but activism has no place in our schools, whether religious, business or social action.  We just can't afford the luxury anymore.


    1. Bilingual for —-

      For the argument about bilingual for those new to the country—do they have a program for Chinese, Japanese, Hindi, south east Asian, German, French, Russian  ? Or is bilinguial just code for Spanish ?

      What about bilingual for training in French, German, Russian that are used for academics ?  What about reading knowledge Latin and even Greek for a sound liberal arts education ?

      1. We need Spanish Training

        For reasons of practicality, District 65 should have district-wide immersion programs in Spanish.  Spanish is the second most widely spoken language in the country.  Spanish is the second most widely spoken langague (by native speakers) worldwide after Mandarin.

        Hispanics are the largest minority group in Evanston. 

        Much like Canada has elementary immersion programs in French throughout the country because of the importance of the French langugage to the country's history and culture, the same should go in the US for Spanish. 

        There is much evidence to suggest that people who are bilingual from an early age are better able to learn a third and forth language.

        Thus, District 202 should have opportunities for Mandarin, Arabic, Russian, French, etc… If a student comes to those classes already bilingual they will be better placed for learning that third language. 

        I am a gringo and went to Evanston schools.  I was able to learn Spanish because I spent several years in Latin America after college, but it was a struggle.  I had friends in Latin America from Canada and Holland who were Spanish beginners, but were already bilingual and they picked up Spanish much quicker than I did.

        I speak only to my kids in Spanish now.  They are not in Dist. 65 yet, but I am worried that they will not develop their skills adequately because of the basic absence of language training there.

  3. Bilingual

    According to state law, a school district must provide bilingual education for non-English speaking students only if they are in a language group that has at least 20 students in the district.  Non-English speaking students in other language groups receive ESL instruction.

    In Evanston, French and Spanish are the foreign language choices in middle school.  At the high school, Latin, German, Hebrew, Chinese, Japanese and ASL are also offered.  

Leave a comment
The goal of our comment policy is to make the comments section a vibrant yet civil space. Treat each other with respect — even the people you disagree with. Whenever possible, provide links to credible documentary evidence to back up your factual claims.

Your email address will not be published. Required fields are marked *