He affirmed, “language acquisition, first or second, occurs when comprehension of real messages occurs, and when the acquirer is not ‘on the defensive’... Language acquisition does not require extensive use of conscious grammatical rules, and does not require tedious drill. It does not occur overnight, however. Real language acquisition develops slowly, and speaking skills emerge significantly later than listening skills, even when conditions are perfect. The best methods are therefore those that supply 'comprehensible input' in low anxiety situations, containing messages that students really want to hear. These methods do not force early production in the second language, but allow students to produce when they are 'ready', recognizing that improvement comes from supplying communicative and comprehensible input, and not from forcing and correcting production”.
Krashen's theory of second language acquisition consists of five main hypotheses:
▪ the Acquisition-Learning hypothesis;
▪ the Natural Order hypothesis;
▪ the Monitor hypothesis;
▪ the Input hypothesis;
▪ the Affective Filter hypothesis.
THE ACQUISITION-LEARNING hypothesis
Adults have two different ways to develop competence in a language: language acquisition and language learning. Language acquisition is a subconscious process not unlike the way a child learns language. Language acquirers are not consciously aware of the grammatical rules of the language, but rather develop a "feel" for correctness. "In non-technical language, acquisition is 'picking-up' a language." Acquisition requires meaningful interaction in the target language - natural communication - in which speakers are concerned not with the form of their utterances but with the messages they are conveying and understanding. Language learning, on the other hand, refers to the "conscious knowledge of a second language, knowing the rules, being aware of them, and being able to talk about them." Thus language learning can be compared to learning about a language.
THE NATURAL ORDER HYPOTHESIS
The natural order hypothesis states that "the acquisition of grammatical structures proceeds in a predictable order." For a given language, some grammatical structures tend to be acquired early, others late, regardless of the first language of a speaker. However, as will be discussed later on in the book, this does not mean that grammar should be taught in this natural order of acquisition.
THE MONITOR HYPOTHESIS
The language that one has subconsciously acquired "initiates our utterances in a second language and is responsible for our fluency," whereas the language that we have consciously learned acts as an editor in situations where the learner has enough time to edit, is focused on form, and knows the rule, such as on a grammar test in a language classroom or when carefully writing a composition. This conscious editor is called the Monitor. Different individuals use their monitors in different ways, with different degrees of success. Monitor Over-users try to always use their Monitor, and end up "so concerned with correctness that they cannot speak with any real fluency." Monitor Under-users either have not consciously learned or choose to not use their conscious knowledge of the language. Although error correction by others has little influence on them, they can often correct themselves based on a "feel" for correctness. Teachers should aim to produce Optimal Monitor users, who "use the Monitor when it is appropriate and when it does not interfere with communication." They do not use their conscious knowledge of grammar in normal conversation, but will use it in writing and planned speech. "Optimal Monitor users can therefore use their learned competence as a supplement to their acquired competence."
THE INPUT HYPOTHESIS
The input hypothesis...