Bilinguals have better social understanding than monolinguals. Also, bilinguals show cognitive advantages. Research showed bilinguals have a little better performance than monolinguals on tasks that involve switching between activities and inhibiting previous learned responses (Bialystok, Craik, & Luk, 2012).
Bilingual people show increased activation in the brain region associated with cognitive skills like attention and inhibition. For example, bilinguals are proven to be better than monolinguals in encoding the fundamental frequency of sounds in the presence of background noise.
On the other hand, some of the disadvantages of bilingualism are an apparent delay in language acquisition; interference between the two phonological, lexical, and grammatical systems; and a possible decrease in vocabulary in both languages.
Bilingualism strengthens cognitive abilities - bilingual people tend to be more creative and flexible. They can be more open-minded, and they also find it easier to focus on a variety of tasks simultaneously. And being able to speak two languages helps in other ways too...
Researchers found that young adults who knew two languages performed better on attention tests and had better concentration compared to those who only spoke one language. They also respond faster or more accurately than their monolingual peers, according to Kapa and Colombo, 2013.
According to 2015 research from the Georgetown University Medical Centre, subjects who spoke two languages (bilinguals) had more gray matter in the brain (a very good thing) and better short-term memory, problem-solving skills, and attention management when compared to those who only spoke one language.
Many studies have shown that bilingual experience can promote the development of children's metalanguage cognition and reading skills. They are found to be better than monolingual children in the flexibility of lexical- semantic connection.
Compared to normal monolinguals, normal bilinguals have more gray matter in these areas, particularly left inferior frontal gyrus, and greater frontal white matter tracts[19,20].
Yet all research points to the exact opposite–not only that, but bilingual students pick up certain pre-reading skills faster than their monolingual classmates. In fact, bilingualism is associated with many other cognitive benefits like stronger multitasking skills, creativity, and working memory.
Bilingual adults and children seem to have social and emotional benefits like being able to show better self-control and internalize negative states like anxiety, aggression, anger, loneliness or low self-esteem less frequently. They have greater tolerance and less racism.
Research has also shown a positive correlation between bilingualism and cognitive development, especially executive function. Bilingualism supports skills that are specific to executive function: careful attention to the target language, suppressing the non-target language and effectively switching between languages.
Switching can be complicated/tiring
Another downside of being bilingual is that switching between languages can be complicated. Even if you're fully fluent in both languages, it's way more than simply translating words. It's translating the meaning.
In the realm of cognitive processing, studies of executive function have demonstrated a bilingual advantage, with bilinguals outperforming their monolingual counterparts on tasks that require ignoring irrelevant information, task switching, and resolving conflict.
Improvements in Learning
22 The bilingual language-learning advantage may be rooted in the ability to focus on information about the new language while reducing interference from the languages they already know.
Many opportunities open up when discussing language. Being monolingual limits you to have an open mind, not seeing how others might live. Citizens who do speak more than one language have the opportunity to experience how different someone's life compared to theirs is.
The acquisition of a second language can in fact benefit from the cognitive development and the academic development. In contrast, learning a second language too early can lead to a loss of the native language and the inadequate mastery of native language makes it more difficult to learn a foreign language.
One disadvantage of being bilingual is that bilingual and multilingual speakers have a smaller vocabulary in the languages they speak than monolingual speakers. In addition to this, the time taken for bilingual speakers to retrieve words when thinking is slower than for a monolingual speaker.
Researchers have shown that the bilingual brain can have better attention and task-switching capacities than the monolingual brain, thanks to its developed ability to inhibit one language while using another.
Learning multiple languages re-structures the brain and some researchers argue that it increases the brain's capacity for plasticity. Language learning boosts brain plasticity and the brain's ability to code new information.
Better Multitasking Skills
Researchers theorize that since bilinguals are constantly processing twice as much language at any given time, their brains are more agile. Even when tasks have nothing to do with language, bilinguals still routinely out-perform monolinguals at handling two or more tasks at once.
Because both of a bilingual person's language systems are always active and competing, that person uses these control mechanisms every time she or he speaks or listens. This constant practice strengthens the control mechanisms and changes the associated brain regions.
Bilingual learning has been shown to be associated with higher cognitive flexibility (Bialystok and Senman, 2004). Cognitive flexibility refers to an individual's ability to switch between different task states and mental stereotypes (Miyake et al., 2000).
By definition 'monolingual' means the ability to speak only one language, 'bilingual' two languages and 'multilingual' several languages.