Kinds of multilingualism
There exists a concept of communicate competence that defines the level of proficiency this or that person has in other (non-mother-tongue) languages. There are two types of communicate competence that is presently distinguished by modern linguists. Needless to say, both definitions are rather relative.
The former group of bilinguals are the so-called compound speakers. They associate phrases of first and foreign languages as the same things. They pay attention to the notions more than to the words. They view all the things as certain ideas that are merely represented through different sound and written combinations in different languages correspondingly. The speakers of this kind are usually admitted to be experienced enough in all digested languages.
The latter group of bilinguals may be related to coordinate speakers. These speakers have to "coordinate" associations for words and phrases in different languages. In this case, both or more languages are not equal in one's mind. The first one seems to prevail over all others and appears to be "background" or a "prism" through which all the other ones are reflected.
No wonder that brought-forward theory stirred a general interest. There is no clearly put difference between two definitions. Some thinkers believe that the only difference comes to grammar, others support "vocabulary" version. There is also a group that denies the possibility of dividing the concept of "multilingualism" at all.
The only obvious conclusion we may arrive at is that bilingualism is the first stage of multilingualism.
