A common assumption is that speaking too many languages leads to speakers confusing one language with another, leading to the inability to learn any one language successfully. Another assumption is that it is impossible to be good at two languages, and that one is likely to suffer.
As Grosjean (1982) pointed out, while we never doubt that the study of mathematics or the pursuit of music is good for our general development, the learning or use of an additional language seems to attract closer scrutiny.
There is no research to indicate that bilingualism will adversely affect stuttering or that a second language will be detrimental to those who are hearing impaired. Furthermore, there is no evidence to suggest that bilingualism is negatively associated with language impairment.
The Early Years
It was in the mid-nineteenth century that possible harmful effects of speaking a second language were formally expressed. Humboldt (1767-1835) argued that it’s only thought monolingualism that we can preserve the essence of each individual language.
A whole series of studies confirmed the inferiority of bilinguals in both verbal and non-verbal tasks. In some studies, they were found to perform poorly only on tests of non-verbal intelligence. These studies spanned four continents and involved 26 different cultural groups. Though more than 50 percent of the studies indicated weak levels of language competence in English for the bilingual population, English was the medium used for testing.
Despite methodological flaws, these studies had considerable influence, and by the middle of the twentieth century the opinion that bilingualism is detrimental to cognitive functioning was firmly established.
The studies between 1922 and 1943 used an assortment of intelligence quotient (IQ) tests as standard tools to measure the cognitive abilities of bilinguals. Studies which factored the language component indicated that bilinguals were not inferior to monolinguals in performance.
Another issue of concern is whether the various IQ tests used were valid measures of intelligence. It is widely recognized that such tests do not measure innate abilities; instead, they contain cultural bias which may place children at a distinct advantage.
The most severe criticism of studies from this early period concerns the inadequate definition of bilingualism and the confounding of SES and ethnicity variables. In a detailed analysis of these studies, McCarthy (1930) reported that more than half of the bilingual schoolchildren came from working-class backgrounds, while the monolinguals were from educated middle-class homes. Furthermore, how bilingual proficiency was measured was problematic.
Bilingualism Enhances Cognitive Functioning
In the first documented case study of a bilingual, Leopold (1949a) cited his bilingual daughter Hildegarde’s metalinguistic awareness as evidence of the enhancing effects of bilingualism. He noticed that she was precociously aware of rhymes and would deliberately destroy rhymes in word play. Leopold argued that bilinguals were able to detach sound from meaning because of the constant early exposure to two languages. So, from a very young age a bilingual child is constantly aware of two competing forms for one meaning.
Peal and Lambert (1962) strictly controlled the SES and language background of the 364 bilingual and monolingual participants in their Canadian study. They screened their sample with great care, matching the children on SES, sex, age, language, intelligence, and attitude. Their study found that once SES and language competence variables were controlled, bilinguals outperformed monolinguals in IQ tests. Moreover, bilinguals were also found to have more positive attitudes towards French-speaking communities than their (English or French) monolingual counterparts had.
Another interesting question arose as bilinguals in Peal and Lambert’s study were found to be not categorically better on all measures of nonverbal tasks. Such task can be divided into two subgroups, one requiring spatial and perceptual processes and the other requiring symbolic manipulation. In spatial and perceptual processes, the emphasis is on spatial acuity and perceptual speed, whereas symbol manipulation tasks require understanding of abstract relations, concepts, and factual information.
In Peal and Lambert’s study, bilinguals were found to be better in the symbolic manipulation types of non-verbal tasks but performed the same as monolinguals in the non-verbal tasks requiring spatial and perceptual processes. Pearl and Lambert called this ability “mental or cognitive flexibility” and proposed that bilinguals’ early awareness of two different codes, and their ability to associate tow words with one object, may have enhanced the development of an increased cognitive flexibility.
Bilingualism and Intelligence
Pearl and Lambert’s own exploratory analysis seemed to indicate that some level of intelligence is essential for bilingualism. However, this does not rule out the fact that bilingualism may in some ways be positive influence on non-verbal abilities.
Hakuta and Diaz (1985) conducted longitudinal study which tracked the relationship between cognition and bilingual proficiency. By assessing both the language proficiency and the cognitive level of bilinguals over time, Hakuta and Diaz presented findings which conclusively supported the hypothesis that it is bilingual proficiency that exerts an influence on cognitive functioning and not the other way round. Hakuta (1987) reanalyzed the longitudinal data and argued that, while the degree of bilingualism was a better predictor of cognitive ability, the reverse was also true, although the effect was not quite as strong. He also reported another set of results, which indicated that there was no relationship between increased bilingual proficiency and the metalinguistic awareness for the bilingual sample, who were drawn mainly from lower socio-economic backgrounds. In this discussion, Hakuta argued that the context in which bilingual function must be taken into account.
Current Views on the Effects of Bilingualism
Since 1965, a stream of papers have highlighted the positive effects of bilingualism and marked a change in research focus. Instead of making a general search for IQ superiority, the new generation of researchers has been far more specific in their enquiry.
Loosely defined, cognitive flexibility is used to mean creativity or ability use divergent thinking, such as the ability to generate multiple associations from one concept, or the ability to mentally reorganize the elements of a problem or situation.
Using the an Embedded Figure Test—a specific task for measuring cognitive flexibility which involve detecting simple objects embedded in larger, more elaborate figures such as the search for multiple hidden objects in the Where’s Waldo? picture book—bilingual children were found to perform significantly better than monolingual children (Balkan 1970; Cummins and Gulutsan 1973).
Broadly defined, metalinguistic awareness is the ability to focus on different levels of linguistic structures such as words, phonemes, and syntax. This ability to analyze language more intensely has been the subject of many studies. Metalinguistic awareness and bilingualism is burgeoning areas of study. Generally, these studies have targeted the following aspects of linguistic structure: word awareness, phonoligical awareness, sentence awareness, and semantic awareness
There are two important interpretations of word awareness: the ability to recognize that the speech stream is composed of discrete units called words, and the awareness that the relationship between words and their meaning is arbitrary.
The Awareness of Word as a Discrete Unit
In a series of studies, Bialystok (1986a, 1986b, 1987a, 1987b, 1988) compared the performance of Grade 1 English monolingual and French-English bilingual children on tasks such as sentence segmentation (word count) and word judgments. The children were read sentences which were either intact or scrambled and asked to count the number of words in each utterance. The number of syllables and morphemes were also manipulated to further examine the child’s concept of a word. In these studies, bilinguals consistently outperformed monolinguals except in the cases of sentences consisting entirely of monosyllabic words.
The Awareness of the Arbitrariness of Language
The very basis of metalinguistic awareness requires the understanding of language is essentially symbolic and that the relationship between form and function is completely arbitrary. In studies Ianco-Worrall (1972) and Ben-Zeev (1977), children were asked to play a game involving symbolic manipulation. For example, they were asked if it was all right to switch names for ‘turtle’ and ‘plane’. They were then asked to play a game where they had to say turtle when they meant plane.
In other tasks, the substitution involved violating grammatical rules of the language. For example, children were told to replace ‘the boy’ with ‘pencils’ when given the sentence ‘The boy sings loudly’.
Here, bilingual children were first pre-tested with Berko’s (1958) Wug Test (The Wug Test is a morphological test which tries to find out if children are able to generalize simple morphological rules such as rules forming the past tense, using novel words). Only children who scored 70 percent and above for the Wug Test were selected to ensure that the violation of grammatical competence in the test language were voluntary and not due to the children’s lack of grammatical competence.
Bilinguals are expected to do better in such tasks as they are more aware of the arbitrariness of language. Hence, they are more likely to reject the notion that one object can only have one name. However, results varied from one study to another.
In a slightly different task with Irish-English bilinguals, Cummins (1978) asked children drawn from Grades 3 and 6 of middle-class Dublin schools to justify their responses to questions. The children were asked, “Suppose you were making up names for things, could you then call the sun ‘the moon’ and the moon ‘the sun’?” ad were then required to justify their response. The children’s justification fell into three categories:
For example, ‘the names could be interchanged because both the sun and moon shine.’
Rigid conventional justifications
For example, ‘they are their right names so you couldn’t change them.’
Arbitrary assignment responses
For example, ‘you could change the names because it doesn’t matter what things are called.’
The findings indicate that bilinguals were significantly more likely to respond with an appeal to the arbitrariness of language and that this tendency was even more pronounced among the children in Grade 6.
Phonological awareness is the ability to recognize that speech is composed of distinct unites of sound. In phonological awareness tasks the children are required to isolate relevant phonological segments as the basis of their analysis. For example, they may e asked to identify the ‘odd one out’, be asked to provide minimal pairs, or supply rhyming words.
Using an assortment of tasks, Davine et al. (1971) found that bilingual children in elementary school in Canada performed better than monolingual children in distinguishing phonological differences. In a study made by Bruck and Genesee (1995), French-English bilinguals were given a battery of phonological awareness tests in both kindergarten and first grade. The findings indicated that bilingual children were better in certain phonological tasks such as syllable counting , while monolinguals were better at phoneme counting.
Sentence awareness is the ability to recognize utterances which are grammatically acceptable within the language. In sentence awareness tasks, the children are often asked to detect, correct, and explain errors. Studies on monolingual children indicate that they have difficulty noting and correcting errors of this kind before the age of 5 to 6. However, Galambos and Goldin-Meadow ((1983) reported that Spanish-English bilingual children who proficient in both languages picked out such errors easily as young as 4 years of age. While young monolingual children focused on the message conveyed, bilingual children readily focused on the structure. In subsequent studies, the findings revealed that bilinguals were better than monolingual at noticing sentence errors but showed no advantages when they had to explain the errors.
The Semantic-Phonetic Preference tasks were used in several studies, and bilingual and monolingual children’s ability to focus on semanitc similarity rather than phonetic similarity was compared. The bilinguals in Ianco-Wrrall (1972) and Ben-Zeev’s (1977) studies were found to give more semantic responses than phonetic responses. Ianco-Worall argued that this preference shows that the child is more able to focus on the meaning and is not tied to the form of the words.
Other studies of semantic awareness look at the children’s ability to form semantic hierarchy and organize objects into superordinate or subordinate categories. There is some evidence (Cummins 1978) to show that bilinguals may have some advantage in this kind of mental organization.
Cummins attempted to resolve inconsistencies in this area by proposing that lower levels of proficiency attained could explain in the lack of advantage found for some bilingual populations. In his hypothesis,
Cummins proposed two thresholds of language competence. He argued that to avoid negative effects form bilingualism, the lower threshold must be attained. The cognitive growth of children who fail to reach the first threshold will be adversely affected. Those who attain the second threshold will enjoy the enhancing effects of bilingualism.
The main problem with the Threshold theory is the difficulty in establishing these thresholds in concrete terms. Given the opaqueness of the concept, the Threshold theory cannot be clearly defined or empirically tested.
Analysis and Control Hypothesis
The central thesis in Bialystok’s (2001a) proposal is that the enhanced metalinguisitc awareness effect operates differently for different linguistic structures. She argues that bilingualism does not have a general effect on a domain of knowledge such as metalinguistic awareness. Rather, the effect is on the underlying cognitive processes that are activated in different tasks.
By focusing o the different task demands, Bialystok (1998) proposed a model whereby bilinguals , irrespective of their degree of bilingualism, may be more advantaged at tasks which place great demands on the control of linguistic processing. However, bilinguals who had attained high levels of proficiency in both languages are also advantaged at tasks that require more analyzed linguistic knowledge. Bialystok identified tow cognitive process, control of attention and analysis of representational structure, which she argues are able to explain the demands in the task. In tasks requiring higher levels of analysis, participants use their knowledge to work out relationships between concepts and ideas, while tasks requiring higher levels of control, participants are required to attend to some features while ignoring or inhibiting their responses to other distracting features.