Professor Li Wei of Newcastle University is a well known researcher on bilingualism. Many bilingual parents intend to stick to speaking one language to their children, but some find themselves switching unconsciously. Professor Li Wei is the leading authority on this area of linguistics and came to talk to our group on 5th March 2005.
Professor Li Wei started by defining bilingualism as the ability to switch instantly between two languages. It can happen at sentence or phrase boundaries, or even within sentences. Technically, this is called a code switch.
There are extremes of bilingualism. At one extreme, people may speak two languages perfectly and never mix them. In reality, this is rare, and tends to be people who have learnt a second language as adults to a very high, professional level, e.g. for teaching the second language. Suppressing code-switching is a skill that has to be learnt, and is not easy. The two languages are always active, therefore an "executive" function controls which language is being used at any one time. Suppressing one language is an active process - therefore harder to maintain when tired.
The other extreme of bilingualism are when neither language is spoken fluently, but both languages are mixed and the person can not speak either of the languages individually.
This has become of concern in New York, where parts of the population have grown up speaking English and Spanish, but unable to speak in just one of the languages. Their entire environment is with people who mix the two languages, and they therefore grow up not distinguishing between the two languages. They are unable to communicate effectively with people who are native speakers of Spanish or English who do not have any fluency in the other language. Indeed such people are not truly bilingual - they are monolingual in a hybrid English-Spanish language.
The vast majority of bilingual speakers are of course in between these two extremes. Switching between languages is actually a sign of a good degree of competence in both languages. Even for children growing up in an environment with both languages, it takes a long time before code-switching is observed. Children will tend to stick with one language until both languages have reached a good degree before they are able to mix or switch between the languages. This is also true for adult learners of a second language. When starting to learn, they are completely unable to mix their own language into the language they are learning. Only once they have grasped the grammar of the second language are they able to include the first language into the second.
Code-switching is a healthy sign of bilingualism. It should not be discouraged, except in a educational environment.
Regarding bilingual children, the very best way to encourage development of bilingualism is to help the child find friends who are also bilingual in the same languages and of the same age group. This can be particularly difficult to find of course. Parents can help enormously by asking questions to the child in a way that evokes complex answers (rather than yes/no questions, or simply giving orders to the child).
Bilingual children benefit substantially from learning more than one language. In addition to the language skills, they tend to have a greater ability to "think laterally". For example, a monolingual child would have a one-to-one relationship between the word "table" and the object itself. A bilingual child, on the other hand, would be well aware that the word "table" is abstract and is just a reference to the actual object, knowing that another language uses a different word for the same object. This separation allows a greater fluidity of thinking in the bilingual mind.
Professor Wei described his own and others' experience of bringing up children to be bilingual. He noted that it is particularly difficult if both parents have the same first language (in his case, Cantonese) and the child is growing up in another language environment. It is actually easier if the two parents have different languages. He explained that unfortunately, and as a terrible generalisation, many Asian and Chinese parents only have friends who are Asian or Chinese themselves. Therefore they speak only their own language, and stick within their own community. (In particular, they are noticeably absent from parent meetings at schools.) Their children, however, have an entirely different experience. They learn English principally with their friends, school, TV, so their experience is of a culture entirely separate from their parents. They want to feel included with their peer-group, so they try particularly had to master English rather than their parents' language. This creates a language-generation gap. The children feel no need to learn their parents' language, and see no advantage in doing so. Of course, they can understand and speak their parents language, but do not code-switch between the two languages. Therefore they are actually monolingual in two languages, rather than being bilingual in two or more languages. The meeting concluded with discussion of families experiences and concerns in this area. The meeting felt that Professor Wei's explanation and advice on bilingualism was positive and very helpful.