Flowers or flores: The neuroscience underpinning bilingualism

By Laima Susta

It is impossible for an Englishman to open his mouth without making some other Englishman hate or despise him. German and Spanish are accessible to foreigners: English is not accessible even to Englishmen.1

The above musings on the complexity of language originate from “Pygmalion”, Bernard Shaw’s play in which he explores the efforts of a poor flower-girl Eliza to acquire an English accent. Throughout the play, Eliza’s success, both financial and societal, seemingly increases after adapting to London’s way of speaking. Shaw shows that proper learning of one’s mother tongue can positively affect one’s life. But what would happen if Eliza, instead of travelling across her home country, arrived in Spain or France? Would she see the world with fresh eyes after having learnt another language? Would her brain fire different signalling pathways when flowers becomes flores?

Shaw touches on the experience of monolinguals, but does not expand to bilinguals, speakers of two languages. However, the differences between the two are becoming extremely interesting for neuroscientists, biochemists and psychocognition researchers. Living in a globalizing world where people speaking at least two languages right from the cradle is not such a rarity drives research of bilingual brains.2 It seems that as a society, we get subconsciously more and more carried away by the magic of mastering languages. So, does the reason for this lie in its advantages?

On a neurological level, both mono- and bilinguals have continually shown significant activity in the left inferior frontal cortex (LIFC) when exposed to languages that they speak. LIFC contains the famous Broca’s area, which was associated with language processing as early as in the late 19th century. Since then, multiple research projects have been conducted to investigate various combinations of bilingual speakers (e.g., early versus late exposure to the second language, low versus high proficiency in the second language) by, unfortunately, leaving monolinguals out of the game. However, in 2008, Kovelman and others directly compared adult monolingual English and early-exposed bilingual English-Spanish speakers.3 As predicted, the speakers had an activated LIFC area when exposed to relevant languages. Interestingly, though, English-speaking bilinguals had higher oxygenation levels of LIFC when exposed to English than monolinguals. This finding suggests that bilinguals might indeed possess a “neural signature”, a specific additional neural pathway or set thereof allowing bilinguals to process the languages. In other words, the bilingual brain might accommodate a wider spectrum of pathways for language processing that would show the true ability of a brain to adapt to different human ways of communication.

To dive deeper, bilinguals are not homogenous: they differ by proficiency, time of exposure, and rate of the first and second language similarity. So, knowing that mono- and bilinguals have potentially varying neural signatures is not enough – maybe there are differences in neural signatures between the bilinguals themselves. In 2013, researchers investigated monolingual children, two-language-speaking children of early (from birth) and late (from ages 4-6) exposure and bilingual adults, identifying brain parts that got activated when participants were exposed to relevant languages.4 The language pool was colourful, including English as a base language both in mono- and bilinguals and French, Cantonese, Greek etc. as bilingual additions. The researchers not only confirmed that the hypothesis of “neural signature” exists as Kovelman suggested in 2008, but they also found that only later-exposed bilinguals recruit fully the usual language-specific (e.g., LIFC) and cognitive-general neural resources. Monolinguals and early-exposed bilinguals did not show the increased recruitment of both brain parts at the same time. Hence, the extent to which the speaker uses different brain resources depends not only on the number of languages they speak but also on the age of exposure to the language.

So far, it is becoming safer and safer to say that bilinguals do have different neural pathways for language processing than monolinguals and the neural resources recruited for language processing themselves vary by the age of exposure in bilinguals. But why do these differences matter? Multiple research projects have repeatedly shown that bilinguals, if compared to monolinguals, perform better in executive functions such as working memory, shifting between tasks, focusing on goals, and eliminating distraction.5 For example, in 2012, Brojde and others looked at the ability of mono- and bilingual children to adapt to different cues in word learning.6 The results suggested that monolingual children were stuck in one type of cue (object) even when others were present, but bilinguals were switching freely between different types of cues (object, pragmatic, social) when they were available. Such findings confirm that bilinguals may adapt better to different – in this case, word learning – environments, which is a crucial skill to have in life. Executive functioning is unilaterally the most important developmental result achieved by children and being exposed to two languages seems to help to achieve this goal. Additional experiments by Kovelman, Jasinska and many other research groups now provide evidence that brain activation does indeed happen differently in bilinguals, and this might explain their better performance in certain executive functions.

Overall, recent research into how bilinguals compare to monolinguals and within themselves provides amazing insights into the ability of the human brain to process languages. The hypothesis of “neural signature” in bilinguals is getting confirmed in almost every study being conducted in the field of psycholinguistics. Additionally, different recruitment of brain areas depending on the age of exposure in bilinguals is also seen more clearly in many recent experiments. Both findings direct researchers to the questions regarding the biochemical basis of bilingualism – to decipher the signature – and multilingualism – perhaps, learning more than two languages results in an even more diverse development of the brain. But this is all to unravel in the future. For now, given the clear advantages of bilingualism, one should always strive to include not only flowers, but also flores in their life.


  1. Shaw, G. B. Pygmalion. The Project Gutenberg; 2003.
  2. Bialystok, E. The Bilingual Adaptation: How Minds Accommodate Experience. Psychological Bulletin Journal. 2017;143(3): 233-262. 10.1037/bul0000099
  3. Kovelman, I., Baker, S. A., Petitto, L.-A. Bilingual and Monolingual Brains Compared: a Functional Magnetic Resonance Imaging Investigation of Syntactic Processing and a Possible “Neural Signature” of Bilingualism. Journal of Cognitive Neuroscience. 2008;20(1): 153-169. 10.1162/jocn.2008.20011
  4. Jasinska, K. K., Petitto, L. A. How Age of Bilingual Exposure Can Change the Neural Systems for Language in the Developing Brain: A Functional Near Infrared Spectroscopy Investigation of Syntactic Processing in Monolingual and Bilingual Children. Developmental Cognitive Neuroscience. 2013;6: 87-101.
  5. Papastergiou, A., Pappas, V., Sanoudaki, E. The Executive Function of Bilingual and Monolingual Children: A Technical Efficiency Approach. Behavior Research Methods. 2021.
  6. Brojde, C. L., Ahmed, S., Colunga, E. Bilingual and Monolingual Children Attend to Different Cues when Learning New Words. Frontiers in Psychology. 2012.

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