Stephen Krashen (University of Southern California) is an expert in the field of linguistics, specializing in theories of languageacquisition and development. Much of his recent research has involved the study of non-English and bilingual language acquisition. During the past 20 years, he has published well over 100 books and articlesand has been invited to deliver over 300 lectures at universities throughout the United States and Canada.
Krashen's theory of second language acquisition consists of five main hypotheses:
* theAcquisition-Learning hypothesis,
* the Monitor hypothesis,
* the Natural Order hypothesis,
* the Input hypothesis,
* and the Affective Filter hypothesis.
According to Krashen, inthe first hypothesis there are two independent systems of second language performance: “the acquired system” and “the learned system”. The “acquired system” or “acquisition” is the product of asubconscious process very similar to the process children undergo when they acquire their first language.
The “learned system” or “learning” is the product of formal instruction and it comprises aconscious process which results in conscious knowledge 'about' the language, for example knowledge of grammar rules.
The Monitor hypothesis explains the relationship between acquisition and learning anddefines the influence of the latter on the former.
It appears that the role of conscious learning is somewhat limited in second language performance. According to Krashen, the role of the monitor isminor, being used only to correct deviations from “normal” speech and to give speech a more “polished” appearance.
The Natural Order hypothesis suggests that the acquisition of grammatical structuresfollows a “natural order” which is predictable. For a given language, some grammatical structures tend to be acquired early while others late. This order seemed to be independent of the learners'...