Bilingualism is a term we use to refer to the use of or fluency in two (or more) languages. In terms of education, we normally mean two languages, where a student may be studying the curriculum in a second language or in the mother tongue, while studying a second language. In terms of EAL, we use the word “bilingualism” in the context of those students who study the curriculum of a school in a second language, that is to say, that they are still acquiring the language of instruction of the school they are studying in. Bilingualism, then, has many contexts and realities. Some of those contexts are outlined below.
In reference to learners:
MONOLINGUAL: A person who has a native language or mother tongue, but does not have any considerable fluency (if any at all) in a second language. This is a person who, essentially, speaks only one language.
PASSIVE BILINGUAL: A person who is fluent in a mother tongue and has knowledge of and understanding in a second language, but is unable to communicate in the second language. This person may have reading and listening skills, but is unable to speak in the second language.
COMPOUND / DOMINANT BILINGUAL: A compound or dominant bilingual is a person who is able to communicate in a second language but at a much reduced level compared to the mother tongue. Proficiency in the mother tongue will be much greater than in the second language.
COORDINATE BILINGUAL: A person who speaks two languages fluently and has developed two clear language systems. This often happens when a child is raised by two parents under two languages. The person is able to speak both languages with relative fluency, but may at times mix (or code switch) some parts of one or both languages
BALANCED BILINGUAL: A person who has equal fluency in two languages, but may not be recognised as a native speaker of either of those languages. There may still be some gaps in both languages, but they operate as separate systems.
AMBIBILINGUAL: A person who has native ability in two languages. There is no mixing or code switching necessary and the person is considered perfectly fluent in both, without interference. This is the goal of EAL and of current practices in bilingual education.
SEMIBILINGUAL(or Semilingual): A person who does not reach native speaker ability in either the first or second language. This is unlike the balanced bilingual in that the balanced bilingual is closer to native ability in both. It is closer in scope to the coordinate bilingual, but both languages will be weaker than the two languages of the coordinate bilingual. A semibilingual will have issues communicating in both the first and second language. This can happen when the parents speak two languages together and mix them, so that the child learns a mix of both languages as one system, instead of acquiring two clearly distinct systems of language. It can also occur as a result of the linguistic/educational environment of a student, even after childhood.
In reference to education (teachers):
SUBTRACTIVE BILINGUALISM: An educational environment where a student learns a second language, and is indeed immersed in it. This experience becomes subtractive because the mother tongue may not be maintained while the second language is being acquired. This has two major linguistic implications. The first is that the mother tongue will deteriorate; the second language is acquired to the detriment of the first; the student may not reach the ambibilingual stage or even the balanced bilingual stage. In some cases, subtractive bilingualism may be a contributing factor to the existence of semibilingualism in students.
ADDITIVE BILINGUALISM: An educational environment where a student has full support of the mother tongue, while acquiring the second language in an immersion environment. This becomes more complicated when the student body is of mixed linguistic background, but that makes mother tongue support and development even more important, as the student may have less exposure to mother tongue environments. The ultimate goal of additive bilingualism (as a language approach) is ambibilingualism (in the students).