The cognitive advantages of bilingualism
With a few disadvantages
Bilingualism in childhood
Bilingualism often starts in childhood with growing up in a house that speaks two languages. Bilingual children reach language development milestones on the same time frame as monolingual children. However, they usually have a smaller vocabulary in each language compared to monolinguals of the same age. Despite usually having a smaller vocabulary, bilingual children don’t learn to read slower than monolingual children, and if the languages they are learning have similar types of writing systems, ability to read in one is usually related to ability to read in the other.
Stronger selective attention in bilinguals
Bilingual people of all ages show an advantage on certain tasks involving “Inhibition of distracting information, switching between tasks, or holding information in mind while preforming a task” (E. Bialystok et. al., 2009). There is debate as to whether this is because of inhibition of unwanted information or stronger selection of wanted information, but the outcome is that bilingual people are generally better at focusing their attention on what is important, and ignoring what is not.
Slower word retrieval
Bilingual people often will take slightly longer to remember the name of a specific object than monolinguals, and will make more errors. Also, when bilinguals have to generate words from a certain category, they will come up with less words in the same time limit than monolinguals. For this test, bilinguals will often continue coming up with words later into the test compared to monolinguals, the just come up with each word slower. The differences in these tests may arise from interference from the language that is not being used.
Slowing the onset of cognitive diseases
Bilingualism may be able to slow the onset and effects of cognitive diseases such as dementia, though the evidence is limited and needs more research. The research that has been done suggests that bilingualism can delay the onset of dementia or Alzheimer’s by as much as 4 or more years, or at least weaken the symptoms for that long.