Cummins' research concluded that the development of competence in the native language serves as a foundation of proficiency that can be transposed to the second language — the common underlying proficiency hypothesis. His work sought to overcome the perception propagated in the 1960s that learning two languages made for two competing aims. The belief was that the two languages were mutually exclusive and that learning a second required unlearning elements and dynamics of the first in order to accommodate the second (Hakuta, 1990). The evidence for this perspective relied on the fact that some errors in acquiring the second language were related to the rules of the first language (Hakuta, 1990). How this hypothesis holds under different types of languages such as Romance versus non-Western languages has yet to undergo research.

Another new development that has influenced the linguistic argument for bilingual literacy is the length of time necessary to acquire the second language. While previously children were believed to have the ability to learn a language within a year, today researchers believe that within and across academic settings, the time span is nearer to five years (Collier, 1992; Ramirez, 1992).

An interesting outcome of studies during the early 1990s however confirmed that students who do successfully complete bilingual instruction perform better academically (Collier, 1992; Ramirez, 1992). These students exhibit more cognitive elasticity including a better ability to analyse abstract visual patterns. Students who receive bidirectional bilingual instruction where equal proficiency in both languages is required perform at an even higher level. Examples of such programs include international and multi-national education schools.

Multilingualism at the linguistic level
Outcomes
Multilingual individuals
Coordinate model