Does it take much effort for a bilingual person to switch languages? A definitive answer to this question has often proved elusive.
Earlier laboratory studies have typically concluded that, yes, changing from one language to another is not straightforward, with researchers having recorded increases in neural activity in “executive control” regions of the brain when people are asked to move from one language to another.
“The main finding in the lab and previous studies is that switching languages is effortful,” said Esti Blanco-Elorrieta, a PhD student at New York University and a member of the NYU Abu Dhabi Institute, which carries out research in this area.
“However, that’s disconnected from the life experience of bilinguals. If you ask a bilingual in the street is it difficult if they switch, often they may say, ‘no’.”
Indeed, bilingual people will often say that they switch from one language to another because this actually takes less effort than speaking continuously in one language.
“If a lot of people say it’s easier, or not particularly hard, then why in the lab do we find it’s harder?” asked Blanco-Elorrieta.
Along with her PhD supervisor, Professor Liina Pylkkänen of NYU, she has carried out experiments to try to answer this question. Their study was funded by the NYU Abu Dhabi Institute and was recently published in The Journal of Neuroscience.
Undertaken with the help of volunteer young adults in the UAE who speak Arabic and English, the work found that, when bilingual people change languages naturally, without being required to, the regions of the brain in charge of exerting control appear to not be involved at all.
This result ties in with the perception of bilinguals that changing languages is not taxing.
“I think the surprising part of the findings is the complete absence of these executive control demands in fully natural conversation or a fully free production [naming] task,” said Prof Pylkkänen.
In a complex experimental set-up designed by the two scientists, 19 Arabic-English bilingual students, all enrolled at NYU Abu Dhabi or UAE University in Al Ain, carried out language-switching tasks involving speaking (“production”) or listening (“comprehension”). The students were native Arabic speakers who were also fluent in English.
Blanco-Elorrieta carried out the experimental work in the neuroscience language laboratory at NYU Abu Dhabi’s campus on Saadiyat island as part of her PhD research.
In the comprehension part of the experiment, the students were asked to press a button to indicate whether a word they heard and a picture they saw matched. In the production part, participants were asked to name as quickly as possible the picture presented on the screen.
The language that they had to use was indicated either by a colour cue or by the person they were interacting with: an imaginary bilingual person or two monolingual people.
In cases where they were interacting with a bilingual person, the students could choose freely to switch languages. In other instances they were being instructed to move from one language to the other depending on the colour cue or the identity of the monolingual individual they were speaking to.
As they carried out these tasks, a magnetoencephalography (MEG) machine recorded the level of electrical activity in different parts of the brain.
When participants were forced to switch languages, increases in activity were found in two key regions: the prefrontal cortex (PFC), the front part of the brain involved in inhibition and executive control, and the anterior cingulate cortex (ACC), which is important for, among other things, error monitoring and conflict resolution.
However, when the language change took place freely, the PFC and the ACC were not activated.
The reason why previous studies may have shown the involvement of these two brain regions during language switches is that, in these earlier pieces of research, participants were being instructed to change languages at particular times, rather than doing so freely.
This latest research suggests that, under normal conditions when two bilinguals are conversing with one another and switching languages freely, these brain regions do not need to be activated. So it seems that switching languages is less effortful than had been thought.
The findings shed light on the phenomenon of “bilingual advantage”, which refers to a number of intellectual benefits often associated with being able to speak more than one language fluently.
Some aspects of this are well established, such as the reduced risk that bilingual people face from neurodegenerative diseases as they get older.
Other potential benefits are less universally accepted, such as the suggestion that bilingual people are better at tasks that require the engagement of executive control centres of the brain.
“You switch languages a lot, so in some sense that executive control 'muscle' gets practice … That's the logic behind the bilingual advantage hypothesis, because it requires this executive control,” said Prof Pylkkänen.
By suggesting that the executive control centres of the brain are, in fact, often not involved when language switches take place under natural conditions, the latest study calls into question the idea that these parts of the brain are likely to be better developed in bilingual people.
Perhaps it is the case, the researchers say, that some bilingual people who are often required to switch languages from outside constraints benefit from it, while bilinguals who are part of bilingual communities in which language switching is rampant do not.
“What this study suggests — doesn’t show, but suggests — is that [the possible bilingual advantage] might be modified by the specific experience of the bilinguals,” said Blanco-Elorrieta.
Since completing the Arabic-English study, the two researchers have carried out work related to speaking and using sign language.
Their research in future may return to issues linked to Arabic and English because, as their recent study indicates, many fascinating questions remain to be answered.