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During a visit to the pediatrician, the nurse heard me speak with a foreign accent and told me to use only English with my child. She said speaking another language would be “confusing” and have long-lasting, detrimental effects on my daughter.
As a Northwestern University professor who has spent more than 20 years studying bilingualism, I knew that was not true. But many new parents trust the “expertise” of ill-informed nurses, doctors, teachers, school administrators, and even family members and follow the misguided advice to speak only English to their children.
In the process, not only do they deprive their children of exposure to another language and culture that would enrich their lives, but also of the cognitive, neural, social, and economic advantages that knowing another language can confer.
One of the biggest downsides to telling parents not to use the native language with their children is that by eliminating the use of the native proficient language, the size and richness of language input at home is compromised.
The richness of input influences language acquisition and cognitive development. The richer the input a child receives — auditory, visual, tactile — the more neurons are firing and the more active the brain is.
When you tell parents to use a language they do not know well, you replace a source of rich linguistic input with a limited one, negatively impacting development.
In spite of persistent myths, there is no empirical evidence that speaking another language to your child will cause the child to stutter, develop language disorders, or lead to hearing impairment. Nor does bilingualism lead to increased incidence of cognitive disability.
On the contrary, the benefits of bilingualism are lifelong.
Overwhelming evidence demonstrates that knowing multiple languages has cognitive, neurological, and even economic, professional, and interpersonal advantages.
Older persons who are bilingual enjoy improved memory relative to peers who speak only one language. Bilingual Alzheimer’s patients exhibit initial symptoms of the disease four to five years later than monolinguals due to greater “cognitive reserve.” The four to five years difference in the onset of dementia may mean the difference between enjoying your grandchildren and seeing them grow, or never recognizing them.
Cognitive reserve refers to the efficient utilization of brain networks to enhance brain function. If the brain is an engine, bilingualism may help to improve its mileage, allowing it to go further on the same amount of fuel.
In children, bilingualism is associated with better performance on some perceptual and classification tasks, as well as increased cognitive flexibility and meta-cognitive skills.
For example, bilingual children learn earlier than monolingual children that objects and their names are not one and the same; one object can have more than one name. This understanding that language is a symbolic reference system is an important milestone in cognitive development.
My own research shows that learning new languages changes how people see, hear, and think about the world. Speakers of different languages differ in their patterns of eye movements when looking at visual scenes and access information differently depending on the language spoken at any given time. Research on bilingualism shows that decision making, memory retrieval, and self-expression vary across languages.
In fact, many children from upper and middle-class families take foreign language lessons at school and some parents pay for private language tutors, support immersion programs, or send students to study abroad for purposes of “enrichment,” because learning and knowing another language is seen as an asset and is to be encouraged.
At the same time, children who are non-native English speakers are discouraged from speaking their native language in schools and elsewhere under the assumption that it will prevent them from learning English and that, in general, their bilingualism is a problem.
This contrast between the two is likely rooted in social reasons that have nothing to do with the effects of bilingualism. Detrimental effects of bilingualism are usually conflated with poverty and socioeconomic status, in part because non-native speakers are sometimes new immigrants with limited resources. But it is poverty — not bilingualism — that is detrimental.
The linguistic diversity around the world means that the majority of the world population speaks two or more languages. The ability to communicate successfully is essential to our global engagement. Actively encouraging and supporting all children to learn more than one language can further help “make America great” as it competes in a multilingual world economy.
An earlier version of this article appeared on LatinoUSA.org.
Viorica Marian is a professor at Northwestern University and the author of the 2023 popular science book THE POWER OF LANGUAGE.
