Second Language Acquisition Theory

"Language acquisition does not require extensive use of conscious grammatical rules, and does not require tedious drill." Stephen Krashen

"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." Stephen Krashen

"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." Stephen Krashen

Krashen states that we can acquire language as children do. On his theory, he give the difference between acquisition and learning.

Acquisition is the unconscious process which children use to develop and to absorb their native language.

Learning is a conscious process, according to http://www.sk.com.br/sk-krash.html, is the product of formal instruction which results in conscious knowledge about the language, for example knowledge of grammar rules.

On Krashen´s theory, there are four hypothesis:

The Input Hypothesis:

According to http://www.sk.com.br/sk-krash.html, in this hypothesis, the learner improves and progresses along the 'natural order' when he/she receives second language 'input' that is one step beyond his/her current stage of linguistic competence.
In Krashen´s view acquisition is better than learning, this hypothesis talks about acquisition process which learners acquired language with the language direct exposition.

The Natural Order Hypothesis:

It express that the grammatical structure acquisition has a natural order, some grammatical structures are acquired earlier than others.

The Monitor Hypothesis:

In this hypothesis we can see both acquisition and learning joined. “According to Krashen, the role of the monitor is - or should be - minor, being used only to correct deviations from 'normal' speech and to give speech a more 'polished' appearance.” http://www.sk.com.br/sk-krash.html

Krashen gives three kind of learners and he classifies them for the monitor use:
1. over-users who always use the monitor
2. under-users who never use the monitor
3. optimal users who use the monitor appropriately

The Affective Filter Hypothesis:

“When learners are bored, angry, frustrated, nervous, unmotivated or stressed, they may not be receptive to language input and so they 'screen' the input. This screen is referred to as the affective filter. This is an imaginary wall that is placed between a learner and language input. If the filter is on, the learner is blocking out input. The filter turns on when anxiety is high, self-esteem is low, or motivation is low”. http://bogglesworldesl.com/glossary/affectivefilter.htm