Krashen's Hypothesis

What are the important factors to learn foreign language?
Many people think that learners can acquire language naturally when the learners are exposed to the target language environment as much as possible. Maybe, most parents who send their children to study abroad believe that. However, I am doubtful if the language environment is the only condition for leaning language.

Thanks to my parents, I had stayed in Canada for 5 years. However, I do not think that my English is better than those who have studied English only in Korea. In retrospect, my personality was the most chief obstacle to leaning foreign languages. I hated that someone pointed out what I was wrong about. Moreover, I really hated that I made same mistakes over and over again in front of other people. Therefore, I tried to avoid using English if possible.

According to Affective Filter Hypothesis by Krashen, a number of 'affective variables' play a facilitative, but non-causal, role in second language acquisition. These variables include: motivation, self-confidence and anxiety. Krashen claims that learners with high motivation, self-confidence, a good self-image, and a low level of anxiety are better equipped for success in second language acquisition. Low motivation, low self-esteem, and debilitating anxiety can combine to 'raise' the affective filter and form a 'mental block' that prevents comprehensible input from being used for acquisition. In other words, when the filter is 'up' it impedes language acquisition. On the other hand, positive affect is necessary, but not sufficient on its own, for acquisition to take place.