The two main views towards bilingualism are, specifically, subtractive bilingualism and additive bilingualism.
Subtractive bilingualism is the perception that the acquisition of L2 would be detrimental to an individual’s L1. This can be caused by the increased cognitive load due to L2 acquisition which consequently decreases competence in users’ L1. This phenomenon is found to be experienced by minority groups, especially when they are not schooled in their L1 (Lambert, 1975). With the frequent usage of their L2, their L1 competence and culture is gradually replaced by the L2.
Opposing this view is, additive bilingualism which suggests that the acquisition of L2 is not detrimental to one’s L1, but is in fact, beneficial to the language user. The term “additive” is used as it portrays an addition to one’s language repertoire. That is, even while learning a second language, one’s first language skills and culture remains valued. Thus, additive bilingualism is seen as the main goal of bilingual education. Total additive bilingualism occurs when one is highly proficient in both the cognitive-academic aspect and communication in both their L1 and L2. Total additive bilingualism is also said to be achieved when one is consistently able to hold onto, and remain positive, in their L1 culture whilst possessing the same attitude towards their L2 (Landry & Allard, 1993).
In addition, Landry and Allard (1993) found that additive bilingualism usually occurs when one’s L1 is of a higher status in the community as compared to the L2. As the L1 is of high status, the community would continue using it in daily activities and thus, it is less likely for one to lose their L1 as well as its culture while acquiring the L2. In most cases, unless one’s L1 is a minority language, additive bilingualism will occur and thus, would bring benefits in both language and cognitive aspects (as mentioned earlier).