In an increasingly internationalised world, bilingualism appears to have become the norm for at least half of the global population. Putting aside the obvious advantage of intercultural communication, in recent decades, the scientific community has observed unquenchable enthusiasm for the cognitive benefits that bilingualism brings. Researchers have since then engaged in repeated experimentation, identifying a multitude of “brainy benefits” linked with bilingual activity, among which include enhanced executive functions, increased attentional control and neural response consistency, improved working memory, more efficient information processing, facilitated task-switching, and potential delay of cognitive decline. Notwithstanding a few critical voices, the scientific community generally posits that while bilingualism does not necessarily make us smarter, it does, in fact, train our brains to be sharper.

This all sounds like great news, but are these effects equally strong among different types of bilinguals? Experimental linguists have probed into varying factors that may affect this—namely, the onset of second language acquisition, second language proficiency level, as well as the extent of bilingual exposure. However, as it currently stands, little attention to date has been placed on the actual language pairs included in the bilingual repertoire—a matter that is actually of key significance. Picture this: Croats who grow up speaking only Croatian as a first language would pretty much be naturally bilingual, given how the Croatian and Serbian languages are almost identical (they are classified into two languages mainly because of political-historical reasons). As such, it wouldn’t be sensible to assume that the cognitive trajectory of a Croatian-Serbian bilingual would develop in the same way as, let’s say, a Croatian-Korean bilingual.

A burning question thus emerges: when it comes to choosing a second language to learn, do different languages train our brain in different ways? 

Research pertaining to this line of inquiry is only at its infancy. The use of magnetic resonance imaging (MRI), electrophysiology, and other cognitive tests have played a pivotal role in uncovering the effects of language learning more generally; it wasn’t until late years that a fraction of scholars became intrigued by whether different languages, with different designs, may stimulate activity in different parts of the brain.

“What can we say about languages with particularly intricate syntactic systems, like Arabic and Russian?”

For some, curiosity in this topic was inspired by Chinese (or some say “the Chinese languages” for linguistic accuracy)—due to how its tones and character-based writing system are known to be notoriously complex. Firstly, the heavy reliance on subtle tones is believed to enhance auditory perceptions—a feature that is advantageous for musical abilities (picture the sounds when a musician tunes her violin). Secondly, compared to alphabet-based, phonology-heavy Indo-European languages, Chinese is a visual and logographic language (“picture-based”), involving visual-spatial memory and intricate processing that map meaning to sound. This explains why English speakers demonstrate more intense connectivity between the brain’s Broca’s and Wernicke’s area during oral communication, while Chinese speakers tend to activate the anterior superior temporal gyrus (equivalent to a critical semantic processor) in addition to the aforementioned areas. While we may now concretise the specific neural pathways involved when processing these two languages, an interesting question concerns the extent to which these differences may actually translate to different cognitive benefits. 

The wave of interest in Chinese compels us to think about other languages as well—after all, Chinese really isn’t the only language claimed to be challenging to learn. If the “stimulus” of Chinese-specific neural activity lies in the nature of its script and tones, then what can we say about languages with particularly intricate syntactic systems, like Arabic and Russian? What about alphabetical languages that are complex in its irregular spelling formats, such as Modern Greek (e.g. where the vowel /i/ may roughly correspond to “οι”, “η”, “ι”, or “ει”)? And what about languages with opaque orthography (i.e. that the way words are spelled are not always the way they are pronounced), just like English? These points, while not explored yet in detail, provide interesting food for thought nevertheless.

In addition to design, linguistic distance between the first and second language likewise stimulates brain development. This is relatively straightforward: if an adult German monolingual were to learn Persian as her second language, she would have to first adapt to a new script (training memory); adjust attentional focus from left-to-right to right-to-left reading (perhaps rewiring elements of the brain’s circuitry); build a new lexical network from scratch (training memory); and navigate through new grammatical systems (enhancing logical reasoning). Indeed, empirical studies have suggested findings of similar nature. Neuroimages have indicated that changes to the brain during the course of language learning tend to differ according to perceptions of second language difficulty—an aspect that could be reasonably relevant to linguistic distance. 

“It is an opportunity for science to appreciate the remarkable creativity that humans have shown in designing languages”

Now, this is not to say that the learning of linguistically similar languages does not produce any cognitive benefits; if anything, we may reasonably posit that it is indeed also very cognitively demanding. When a Spanish speaker decides to learn Portuguese as a second language, she is compelled to concentrate and identify small, subtle differences amidst large bodies of similarities (compare “una de las dietas más saludables del mundo” vs. “uma das dietas mais saudáveis ​​do mundo”)—which may somewhat mirror mental activity during “spot-the-difference” types of tasks. The cognitive benefits come greater when she engages in form production (and not just reception of input)— she activates long-term memory of her first language, critically filtering forms that don’t apply to the second language while filling in the accurate ones.

This area of inquiry is still developing in its early days, yet it carries incredible scientific potential. It is an opportunity for science to appreciate the remarkable creativity that humans have shown in designing languages, as well as the extended value of language diversity. In an era where translation software strives and second language learning seems to have been rendered redundant, we may still confidently persuade skeptics that the cognitive essence of language learning is, and will always be, irreplaceable.