Krashen's L2 Acquisition Theory proposes five main hypotheses about second language acquisition: 1. The Acquisition-Learning Hypothesis distinguishes between subconscious acquisition and conscious learning, positing that acquisition is more important and is facilitated by comprehensible input. 2. The Natural Order Hypothesis claims that grammar structures are acquired in a predictable order, which may differ between first and second languages. 3. The Monitor Hypothesis describes the limited role of learning as a "monitor" or editor, only used when speaking or writing with time and focus on form. 4. The Input Hypothesis states that language is acquired through comprehensible messages that are slightly above one's current

1. Stephen Krashen’s L2
Acquisition Theory
Compiled by Doris Shih

2. Outline for Today
The acquisition-learning hypothesis
The natural order hypothesis
The monitor hypothesis
The input hypothesis
The affective filter hypothesis

3. What are the causative variables in
second language acquisition?

4. For you, does language teaching really
help? When does it help and when
does it NOT help?

5. Effecting Variables
Comprehensible input (causative)
Strength of the filter (causative)
Language teaching
Exposure variable
Age
Acculturation

7. The Acquisition-Learning
Hypothesis
Acquisition = subconsciously picking up
Learning = conscious
• Error correction
• Explicit instruction
Children acquire language better than adults

8. The Natural Order Hypothesis
Grammar structures are acquired in a
predictable order
L2 learning order is different from L1 order
L2 learning adults and children show
similar order

9. ING (progressive)
PLURAL
COPULA (“to be”)
AUXILIARY
ARTICLE
IRREGULAR PAST
REGULAR PAST
SINGULAR (-s)
POSSESSIVE (-s)
The order for L2 learners (Krashen, 1977)

10. The Monitor Hypothesis
Acquisition has the central role
Learning functions as a Monitor
3 conditions needed to use Monitor
• Time
• Focus on form
• Know the rule
When Monitor is not used, errors are
natural
Pedagogically: study of grammar has a
place, but a limited one

11. The Input Hypothesis
We acquire by comprehensible input (i) + 1
Input Hypothesis relates to acquisition, not
learning
Focus not on structure but on understanding the
message
Do not teach structure deliberately; i+1 is
provided naturally when input is understood
Production ability emerges. It’s not taught directly

12. The Affective Filter Hypothesis
Motivation
Self-confidence
Anxiety
Lower affective filter will go further

13. Language
Input
Affective Filter
Acquired
Competence
Language Acquisition
Device
The affective filter

14. Reference
Krashen, Stephen D. Principles and Practice
in Second Language Acquisition. New
York, NY: Prentice Hall, 1987.