Krashen's theory of second language acquisition consists of five main hypotheses: the acquisition-learning hypothesis, the monitor hypothesis, the natural order hypothesis, the input hypothesis, and the affective filter hypothesis. The acquisition-learning hypothesis distinguishes between acquired unconscious knowledge and learned conscious knowledge, stating that acquisition is more important for language development. Acquisition involves meaningful interaction, while learning involves formal instruction and error correction.

1. Krashen’s Theory
 Much has been made of Krashen’s theory of second language
acquisition, which consists of five main hypotheses:
 The acquisition learning hypotheses
 The monitor hypotheses
 The natural order hypotheses
 The input hypotheses
 The affective filter hypotheses

2. Acquisition Learning Hypotheses
 According to Krashen’s acquisition learning hypotheses, there
are two independent ways to develop our linguistics skills:
acquisition and learning
 This theory is at the core of modern language acquisition
theory, and is perhaps the most fundamental of Krashen’s
theories of second language acquisition.

3. Acquisition
 Subconscious process where individual is not aware. One is
unaware of the process as it is happening and when the new
knowledge is acquired, the acquirer generally does not realize that
he or she possesses any new knowledge.
 According to Krashen, both adults and children can subconsciously
acquire language, and either oral or written language can be
acquired. This process is similar to the process that children
undergo when learning their native language
 Acquisition requires meaningful interaction in the target language,
during which the acquirer is focused on meaning rather than form

4. Learning
 Learning a language on the other hand is a
conscious process, much like what one
experiences in school. New knowledge or
language forms are represented consciously in the
learner’s mind, frequently in the form of
language “rules” and “grammar” and the process
often involves error correction. Language
learning involves formal instruction, and
according to Krashen is less effective than
acquisition.

5. The term learning refers to conscious knowledge of a
second language, knowing the rules, being aware of
them and being able to talk about them
In non-technical terms, learning is “knowing about” a
language, known to most people as “grammar” or “rules”
Some synonym include formal knowledge of a language,
or explicit learning

6.  For Krashen, acquisition is by far the more important process
 He asserts that it is only acquire language which readily available for
natural, fluent communication
 Further, he asserts that learning cannot turn into acquisition, citing as
evidence for this that many speakers are quite competent without ever
having learning rules, while other speakers may “know” rules but continue
to break them when they focusing their attention on meaningful interaction
rather than on the application of grammatical rules for accurate
performance

7.  Error correction has little or no effect on subconscious
acquisition, but it is thought to be useful for conscious
learning
 Error correction supposedly help the learner to induce or
“figure out” the right form of a rule. If of example, a student of
English as a second language says “ I goes to school
everyday” and the teacher corrects him or her by repeating
the utterance correctly, the learner is supposed to realize that
the “s” ending “goes” with the third person and not for the first
person, and alter his or her conscious mental representation
of the rule.

8. Some second language theorists have assumed that
children acquire, while adult can only learn
The acquisition-learning hypotheses claims, however,
that adults also acquire, that the ability to ‘pick up”
language does not disappear at puberty
This means that adult be able to achieve native-like level
in a second language. It does not mean that adults can
access the same natural “language acquisition device”
that children use

9. Evidence from child language acquisition confirm
that error correction does not influence acquisition to
any great extent
Brown and his colleagues have shown that parents
actually correct only a small portion of the child’s
language.