Vocabulary size and verbal fluency According to a study on lexical access, monolinguals often maintain a wider
vocabulary in a target language relative to a comparable
bilingual, and that increases the efficiency of word retrieval in monolinguals. Monolinguals also access words more often than bilinguals in a target language. In letter fluency tasks, monolinguals in the study were also able to respond with more words to the letter cue than bilinguals, but such an effect was not seen in bilinguals with a high
vocabulary score. Also, monolinguals performed better than bilinguals on verbal fluency in the study. If the vocabulary abilities were made to be more comparable, however, many of the differences would disappear, indicating that
vocabulary size may be a factor that moderated a person's performance in verbal fluency and naming tasks. The same study also found that bilinguals, in a version of the letter fluency task that placed more demand on executive control, performed better than monolinguals. Thus, once
vocabulary abilities were controlled, bilinguals performed better on letter fluency possibilities by the enhanced frontal executive processes in the
brain. Bilinguals' overall vocabulary size in both languages combined was equivalent to monolinguals' in one language, even though monolinguals may excel in vocabulary size for the one language they speak. Bilinguals may have smaller vocabularies in each individual language, but when their vocabularies were combined, the content size was approximately similar to that of the monolingual. Monolingual children demonstrated larger vocabulary scored than their bilingual peers, but bilingual children's vocabulary scores still increased with age, just like the monolingual children's vocabulary scores (Core et al., 2011). Despite a variation in vocabulary scores, there was absolutely no difference between monolingual and bilingual children in terms of total vocabulary size and total vocabulary gains (Core et al., 2011). Bilingual children and monolingual children have the same vocabulary size and gain the same vocabulary knowledge.
Creative functioning In a study testing for creative functioning that involved monolingual and bilingual children in
Singapore, researchers found that monolinguals performed better on fluency and flexibility than bilinguals. The trend was reversed, however, on tests for originality and elaboration.
Mental well-being In another recent study in
Canada, it has been shown that monolinguals were worse at the onset of
senility than bilinguals. In the study, it seems that being
bilingual is associated with a delay of
dementia by four years as compared to monolinguals. Bialystok's most recent work also shows that lifelong bilingualism can delay symptoms of
dementia. It is believed that bilingualism contributes to
cognitive reserve by preventing effects of cognitive delay and prolonging the onset of sicknesses such as dementia. Cognitive reserve refers to the idea that engaging in stimulating physical or mental activity maintains cognitive functioning (Bialystok et al., 2012). In that case, knowing more than one language is similar to stimulating mental activity. To test whether or not bilingualism contributes to cognitive reserve, Bialystok et al. (2012) looked at hospital records among monolingual and bilingual adults who have dementia. The researchers found that elderly bilingual adults were diagnosed with dementia about three to four years later than elderly monolingual adults. The results have been replicated and validated, with outside factors being controlled. In fact, outside factors such as socioeconomic status and cultural differences always helped monolinguals, making the argument the bilingualism contributes to cognitive reserve even stronger (Bialystok et al., 2012). That finding enhances the fact that bilinguals are at an advantage because of their ability to speak two languages, not because of outside factors. A probable explanation for this phenomenon is that knowledge of multiple languages keeps the brain alert and therefore more mentally aware for a longer period of time.
Emotion and behavior A study conducted with children in their early school years suggested that there are emotional and behavioural benefits to being bilingual. In the same study, the findings show that monolingual children, in particular non-English monolingual children, display more poor behavioural and emotional outcomes in their school years. The non-English monolingual children had the highest level of externalizing and internalizing behavioral problems by fifth grade (around 10–11 years of age), even though the children were all measured to have similar levels of internalizing and externalizing behavioral problems at the start. In contrast, the fluent
bilingual and non-English dominant bilingual children were found to have the lowest level of these behavioural problems. The authors suggest that monolingualism seems to be a risk factor. However, if there is a supportive school environment with teachers who are experienced in
ESL (English as a Second Language), children seem to have better emotional constitution.
Memory performance In a study conducted at the
University of Florida, which compared Native-English
bilinguals to English monolinguals, although there was no difference in accuracy between the two groups, there was a slower response rate from bilinguals on tasks that involve latency of recognition of a list of abstract words and
lexical decision tasks, but not in any of the other tasks used in their study. The researchers noted that the tasks where bilinguals had a significant disadvantage were those which were data-driven (subjects were given verbal input and asked to make decisions about it), as opposed to conceptually driven (subjects were asked to produce verbal output). The study differed from prior research in that the bilingual subjects were more balanced in their familiarity with their two languages. Mägiste hypothesized that the bilingual disadvantage could have been due to differential familiarity with the dominant language. They explained that for bilinguals, it could be because the acquiring and using of the
second language meant that there was less time to process the
first language, as compared to the monolingual participants in the study. However, evidence from a research study shows that bilinguals have a faster reaction time in most working memory tasks. While a lot of research asserts that monolingual children outperform bilingual children, other research asserts the opposite. Research by Bialystok et al., as reported by Kapa and Colombo (2013, p. 233) shows that bilingual individuals perform better than monolingual individuals on a wide variety of cognitive tests, thus demonstrating cognitive control advantages. Two different concepts, attentional inhibition and attentional monitoring, are used to measure attentional control. In terms of attentional control, early bilingual learners showed the greatest advantage, compared to monolingual speakers and late bilingual speakers. In terms of overall performance on ATN, the three groups performed equally, but when age and verbal ability variables were controlled, there was a difference in reaction time. The early bilingual children's reaction time was tremendously faster than the monolingual children, and only slightly faster than the late bilingual children (Kapa & Colombo, 2013). Early bilingual learners showed that they simply responded most efficiently to the task at hand. The results from this study demonstrate the advantages bilingual children have with attentional control. This is likely because bilingual children are used to balancing more than one language at time, and are therefore used to focusing on which language is necessary at a certain time. By constantly being aware of what language to use and being able to successfully switch between languages, it makes sense that bilingual children would be better at directing and focusing their attention.
Verbal and non-verbal cognitive development A 2012 study by the
University of York published in
Child Development journal reviewed the effects of the development of a child's verbal and non-verbal language, matched between monolinguals and bilinguals in a particular language. Researchers compared about 100 6-year-old monolingual and
bilingual children (monolingual in English; bilingual in English and Mandarin, bilingual in French and English, bilingual in Spanish and English), to test their verbal and
non-verbal communication cognitive development. The research takes into consideration factors like the similarity of the language, the cultural background and education experience. These students mostly come from public schools from various areas, having similar social and economic background. Results show that in the child's early stage, multilingual kids are very different from one another in their language and
cognitive skills development, and also when compared to monolingual children. When compared to monolinguals, multilingual children are slower in building up their
vocabulary in every language. However, their metalinguistic development allowed them to understand better the structure of the language. They also performed better in non-verbal control tests. A non-verbal control test refers to the ability to focus and then able to divert their attention when being instructed to. ==Reasons for persistence==