This document outlines Stephen Krashen's 5 hypotheses about language acquisition: 1) The Acquisition-Learning Hypothesis distinguishes between implicit acquisition and explicit learning; 2) The Monitor Hypothesis describes how learners develop an inner grammar monitor that can hinder fluency; 3) The Natural Order Hypothesis claims grammatical structures are acquired in a predictable order; 4) The Input Hypothesis posits that acquisition occurs through comprehensible input just beyond one's current stage; 5) The Affective Filter Hypothesis suggests affective variables can block input, so teachers should create a low-anxiety environment.

1. TESOL 510
Principles of Language
Learning & Teaching
Stephen Krashen’s
5 Hypotheses

2. The Innatist Model:
Krashen’s 5 Hypotheses
1. The Acquisition/Learning Hypothesis
2. The Monitor Hypothesis
3. The Natural Order Hypothesis
4. The Input Hypothesis
5. The Affective Filter Hypothesis

3. #1: The Acquisition-Learning
Hypothesis
 According to Krashen, acquisition and
learning are not the same.
 Acquisition = implicit, subconscious, learned
through natural communication and
interaction
 Learning = explicit, conscious, learned
through formal language study

4. #2: The Monitor Hypothesis
 Learners gain a language “monitor” that pays
attention to grammar and form
 The monitor can be a hindrance, as it causes
the learner to focus more on accuracy than
on fluent communication
 Teachers must balance accuracy and fluency

5. #3: The Natural Order Hypothesis
 Grammatical forms are aquired in a specific
order

6. #4: The Input Hypothesis
 Acquisition occurs when learners receive
input that is one step beyond their current
language development ( i + 1)
 Krashen argues that authentic
communication naturally provides
comprehensible input at i + 1

7. #5: The Affective Filter Hypothesis
 Affective factors such as stress, self-
consciousness, and low motivation can
prevent input from being processed by the
brain, and prevent acquisition
 The implication is that teachers need to
“lower the affective filter” by providing a low-
stress environment for language practice.