For over sixty years scientists and linguists have been doing the researches about the second language acquisition and bilingualism among children. It has been discovered that second language acquisition is a parallel of the first language acquisition but also there are a lot of differences. At the beginning it must be said what the bilingualism and second language acquisition are. SLA (Second Language Acquisition) refers to the process by which people learn second language that means that they know one language and then start learning the other one. On the other hand, bilingualism refers to the ability to use two languages with equal fluency. But some scientists believes that even though those abilities are nearly equal, one language will always dominate above the other. There are three types of bilingualism: * Simultaneous: learning both languages as the first one. So a new born child who does not speak any languages goes directly to the phase that it speaks two languages; * Receptive: it means that children are able to understand two languages but express themselves only in one; * Sequential: refers to the acquisition of the second language after establishing the first one. As for the second language acquisition, there is main theory elaborated by the psycholinguist, Stephen Krashen, which consist of the five hypothesis: 1. The Acquisition-learning hypothesis. There are two independent systems: the acquired system and the learning system. Acquisition is the product of subconscious process, needs natural conversation in which speaker is focused on the communicative act, not on the form. It can be compared with the acquisition of the mother tongue by the child. Learning, on the other hand, is the product of formal instructions, so it is the conscious process. This is represented by the norms grammar, vocabulary and so on. It demands effort and attention. Krashen emphasizes that acquisition is more important than learning. 2. The Monitor hypothesis. This hypothesis explains the relation between acquisition and learning. As the acquisition is the initiator of the utterance, the learning is the editor. The function of monitor is, according to Krashen, to correct “deviations from normal speech and to give speech a more polished appearance”. 3. The Natural Order hypothesis. It is based on the claim that the acquisition of grammatical structures follows a natural order that can be predictable. It is also said that some grammatical structures are learnt earlier and some later and they seem to be depended on the learner’s age. 4. The Input hypothesis. This hypothesis explains, according to Krashen, how the second language is acquired. It explains only the acquisition not learning. This hypothesis shows that the learner processes along the natural order when one receives second language input that is beyond one’s current stage of linguistic competence. 5. The Affective Filter hypothesis. According to this hypothesis, there are some affective variables that are facilitative in second language acquisition. These are for example motivation, anxiety and self-confidence. It was claimed that learners with high motivation and self-confidence and low level of the anxiety are better “equipped” for success in second language acquisition. From the beginning of life, babies acquire their first language due to the same pattern. All children go through the same phases. These are: * bubbling,
* one-word utterance,
* two-word phrases,
* full sentences,
* complex grammar.
As it is generally said, children acquire second language faster than adults. Children who are younger than 6 years old learn two languages as one. As one of the Harvard professors, Patton Tabors, in his book One Child, Two Languages: A guide for Preschool Educators of Children Learning English as a Second Language (1997, p. 12) noticed that “For these children, then, second-language...