Stephen Krashen... This American linguist and professor born in Illinois, revolutionized the way we thought about second language learning. Not much is said about his personal life. Regarding his educational background, it is known that he obtained a Ph.D in linguistics at the University of California in 1972.  From the late 1970s onwards he proposed a series of hypotheses, that supported his theory of second language acquisition. There are five main hypotheses. These are the following:

The acquisition learning hypothesis: It tells us that there are two systems in second language performance. One is the acquired system (Product of a subconscious process. Requires meaningful interaction in the target language), and the other is the learned system (Product of formal instruction).

The monitor hypothesis: The monitoring function is the practical result of learned grammar. According to Krashen, the acquisition system is the utterance initiator, while the learning system performs the role of the monitor. The monitor acts in planning, editing and correcting function when the specific conditions are met. Despite the importance of conscious learning, Krashen suggested learner should be focused more on unconscious one. Due to the fact that thinking to much about the accuracy of our sentences before uttering would slow down the learning process.

The input hypothesis: It is only concerned with acquisition. According to this hypothesis, the learner improves and progresses when they receive the second language input that is one step beyond their current stage of linguistic competence. For instance, if a learner is at a stage ¨i¨, the acquisition takes place when they are exposed to ¨Comprehensible input¨ that belongs to level ¨i plus 1¨. Ergo, we can define Comprehensible input as the target language that the learner would not be able to produce.

The Natural Order hypothesis: Acquisition of grammatical structures follows a natural order, which is predictable. For a given language, some grammatical structures tend to be acquired early while others late. This order was independent of the learner´s age, L1 background, conditions of exposure to the target language, etc.

Affective filter hypothesis: In order for meaningful learning to take place, learners should be motivated and relaxed.  Otherwise, it would be a lot harder to acquire or learn a second language. The mental block that is created when our anxiety levels are high is called an affective filter. When it is high, we cannot concentrate, and so the filter impedes language acquisition. On the other hand, when the affective filter is low, we feel relaxed and confident. Therefore, we can receive comprehensible input in the best way possible.

Most of us know this guy is a world-wide known genius in the field of linguistics who does not need to be fawned on whatsoever. Besides, in his speeches, his theories are explained in such a simple way, that there is no need for them to be reworded. Apart from that, he knows how to regale his audience with his fantastic sense of humor. We can infer this instance from Krashen way of seeing second language learning. An aspiring English learner, should contrive to learn this language despite not living in an English speaking country. If they use the right tools to achieve their purpose, there is no reason why they should not succeed. In fact Stephen said once that we all learn a second language the same way. I will leave you with one of his talks before I mop up this writing. P.S. Think about your second language learning. Is it worth it to flit from course to course without learning much? Which approach should you consider?