Why would anyone be interested in becoming multilingual (defined as being able to speak more than one language)? This is an interesting question because instantly we may have a prompt answer in mind—seriously, it is a cherished talent that gives an edge in your career and less seriously, it can be pretty cool. Well, it’s not that simple. Most people, even including many multilingual people themselves perhaps did not know what exactly such multilingualism can bring to them. Since a typical form that can represent multilingualism is bilingualism, let’s look at this population slightly closer.
Numerous studies have all pointed to the fact that benefits of being bilingual extend well beyond bilinguals’ apparent ability to speak another language itself but also include advantages in non-linguistic cognitive domains.
One of the most established facts is that bilinguals have better “Executive Functions” (EF). EF involves the capability of planning, problem-solving, inhibition of habitual responses, cognitive flexibility and control of attentions (although notably EF should not be confused with intelligence, or IQ, which is another domain of general cognition). For example, in a typical EF task, Simon task, participants will see two kinds of stimuli and one stimulus is presented on either the left or the right half of the screen. Participants are instructed to press one of the two keys that are laid left-to-right in front of them. However, even though they are told to select the key only according to the stimuli, they still tend to press the key congruent with the location of the stimuli presented on screen (left key for whatever presented on the left half and so forth).
Numerous studies have established that bilinguals significantly outperform their matched monolingual counterparts in the Simon task and other EF tasks and that such advantage in EF seem to be life-long. Moreover, researches in Alzheimer’s disease (AD) also point out that being bilingual can effectively delay the onset of AD by an average of 5 years. This might be attributed to the better EF that bilinguals possess which can better resist the cognitive decline as the brain ages.
“Simultaneous bilingual” children are even better off than “sequential bilinguals”
Many of the bilingual population in the world are what experts call “sequential bilinguals”. That is, they learn their second language well after their native language is already established. Anyone who has learned a foreign language would acknowledge that the process towards high proficiency in the second language is very painstaking. Worse still, although a lot of energy and time are devoted to this cause, the best outcome possible for all sequential bilinguals is at a near-native level because research has shown that there are certain aspects and features of a language that can never be really acquired as a sequential bilingual (phonologically and syntactically). For example, even very high-level speakers of English as a second language can still make mistakes in the usage of the little articles (a and the) which English native speakers can apparently deal with most ease.
The situation of sequential bilingualism is in stark contrast with another type of bilingualism, “simultaneous bilingualism”, as experts would call. Simultaneous bilinguals possess each language as the first language just like a monolingual person of that language. Yet what most people marvel at is the ease with which simultaneous bilinguals seem to enjoy when they acquire both languages since infancy. Moreover, simultaneous children in general have one year advantage over monolingual counterparts in the development of the ability to understand other people’s mental states (for example, you know that other people may not know some information you have; this is what experts call Theory of Mind), probably due to the exercise of their Executive Functions.