Lessons from the littlest linguists

Sam Goldstein Ph.D. :

One of the first myths bilingual children debunk is that speaking two languages creates confusion. The ability to switch between languages-code-switching-is a sophisticated strategy, not a failure of memory or identity. Studies show that young bilinguals use code-switching to fill lexical gaps, manage complex social contexts, and maintain fluency across both languages (Kaushanskaya & Crespo, 2021).
This fluidity also influences how we measure language knowledge. Bilingual children may know fewer words in each language individually. Still, their total understanding across both languages matches or exceeds that of monolingual peers (Pearson, Fernández, & Oller, 1993). For example, a child might know the word “dog” in English and “perro” in Spanish, registering one label per language, but both point to the same underlying concept. Counting only words per language misses this bigger picture. This insight has direct implications for educational assessments and interventions that tend to rely heavily on monolingual benchmarks.
Input quality and quantity significantly impact bilingual development. Exposure to a language through a variety of high-quality sources contributes to a stronger vocabulary and more complex grammatical structures. The more frequently children hear and use a language in meaningful contexts, the more advanced their skills in that language become (Hoff et al., 2012). A related study indicated that bilingual children exposed to live dialogue, reading, and various multimedia performed better linguistically than their peers with less diverse input (Sun, 2020). Rich input-especially when involving real interaction-fuels deeper language acquisition.

Brain Plasticity and Cognitive Benefits
Neuroscientific research into bilingual children highlights the lasting effects of early language exposure. Even children who stop using a language early in life retain neural signatures of that language. For instance, Chinese children adopted into French-speaking families, although no longer fluent in Chinese, exhibit distinct brain responses to Chinese sounds years later (Pierce, Klein, Chen, Delcenserie, & Genesee, 2014). This suggests that early exposure wires the brain in enduring ways, even without ongoing reinforcement.

These findings support the idea of a critical period for language learning. During early development, the brain is more adaptable and better equipped to create the complex networks needed to manage multiple languages. However, learning remains possible later in life. Adults can still achieve fluency in new languages, although the process usually requires more structured input and practice. The brain’s plasticity never entirely disappears; it becomes more task-specific with age (Werker & Hensch, 2015).

Moreover, growing up bilingual enhances executive control functions such as attention, inhibition, and task-switching. Bilingual children often outperform their monolingual peers on cognitive flexibility and problem-solving tests (Bialystok, Craik, & Luk, 2012). These advantages extend beyond language, providing mental agility that can help in academic and social situations and may even delay cognitive decline later in life.

Applying the Insights
What does this mean for our approach to language learning and teaching? First, it’s essential to stop viewing bilingualism as a deficit or an exception. Bilingual children show that it’s not only possible but often beneficial to grow up navigating two linguistic systems. Their experience demonstrates that learning languages involves not just memorizing words but constructing systems of meaning across different codes.

Second, educators and caregivers must focus on children’s input. Passive exposure-such as television-cannot replace active engagement through conversation, reading, and meaningful interaction. Quality is just as important as quantity. A bilingual child who regularly interacts with speakers of both languages is likely to develop more balanced proficiency than one who hears only fragmented input in one of the languages.

Finally, bilingual children remind us that language is deeply connected to cognition. Their experiences demonstrate how skills in one language can transfer to another. Phonological awareness developed in a child’s first language can significantly aid them in learning to read in a second language (August, Carlo, & Calderón, 2005). Rather than separating the two languages, learners benefit from constructing bridges between them. This transfer effect is powerful in early education, where supporting a child’s home language can enhance their performance in a second language.

Bilingual children are not just exceptions to the rule-they are evidence that the human brain is designed for multilingualism. They demonstrate that flexibility, early exposure, and rich interaction create strong language users and sharper thinkers. By learning from their methods of learning, we can reshape how we teach, support, and value language learning across all ages.