Acquisition vs Learning

Krashen's Acquisition-Learning Hypothesis (1982) draws a sharp line between two ways of developing knowledge of a second language. This distinction is the foundation of the Monitor Model and one of the most debated claims in SLA.

The Distinction

	Acquisition	Learning
Process	Subconscious	Conscious
Knowledge type	Implicit, procedural	Explicit, declarative
How it happens	Through meaningful exposure to comprehensible input	Through study of rules and patterns
Feels like	"Picking up" language naturally	Knowing about the language
Parallel in L1	How children acquire their first language	Not applicable; children don't "learn" L1 rules
Role in production	Initiates utterances	Only monitors/edits (see Monitor Model)

The Non-Interface Position

Krashen's most controversial claim: learning cannot become acquisition. The two systems are separate and non-convertible. No amount of rule memorization will transfer into the acquired system. A learner who memorizes the third-person -s rule has learned it; they will only acquire it through sufficient meaningful input containing that feature.

This is called the non-interface position: there is no interface between the two knowledge systems.

The Interface Counterargument

Multiple theories challenge this strict separation:

• Skill Acquisition Theory (DeKeyser 2007) argues that explicit declarative knowledge does become procedural/automatic through practice (the same process as learning to drive). Conscious knowledge is the starting point, not a dead end.
• The Noticing Hypothesis (Schmidt 1990) proposes that conscious attention to form is a necessary condition for input to become intake. This implies that conscious processing plays a role in acquisition, not just alongside it.
• Weak interface position: Explicit knowledge facilitates acquisition by helping learners notice relevant features in input, even if it does not directly convert.

Why It Matters

The practical stakes are high. If Krashen is right:

• Grammar teaching is largely a waste of time for acquisition (though it may satisfy learner expectations)
• Maximizing meaningful, comprehensible input should be the primary goal
• Classrooms should simulate naturalistic acquisition conditions

If the interface position is right:

• Explicit instruction accelerates acquisition by directing attention to forms
• Focus on Form during communicative activities is valuable
• Grammar teaching works, but only when combined with opportunities for meaningful practice

Where the Field Stands

Most current SLA research supports a weak interface position: explicit knowledge does not automatically become implicit, but it facilitates the process by enabling noticing, monitoring, and focused practice. Pure acquisition-only and pure learning-only approaches are both incomplete. The most effective teaching combines meaning-focused input with strategic attention to form, which is essentially the rationale behind Focus on Form and Form-Focused Instruction.