The Research-Practice Gap
5 SLA Findings That Should Change Your Teaching
Krashen's i+1 hypothesis — learners need slightly challenging input to acquire language — has robust support. But input alone produces comprehension, not necessarily production. Students need both rich input AND structured opportunities to produce language.
Merrill Swain's Output Hypothesis: when students are required to produce language (not just understand it), they notice gaps between what they want to say and what they can say. This 'noticing the gap' is a uniquely powerful acquisition trigger that input alone doesn't create.
Long's Interaction Hypothesis: negotiation of meaning (when communication breaks down and both parties work to restore it) creates the most powerful acquisition conditions. Simulated conversation doesn't replicate this — genuine communication with genuine information exchange is necessary.
For 30 years, the debate was whether explicit grammar instruction helped at all. The consensus now: explicit instruction (teaching rules explicitly) helps learners reach accuracy faster, particularly for complex structures. It doesn't replace input, but works alongside it.
Dörnyei's research on L2 motivation shows that the most powerful motivational driver is the 'Ideal L2 Self' — the vivid image of oneself as a competent user of the language. Teachers who help students envision this ideal self have more motivated and more successful students.
SLA in Practice
Input + Output
Both are necessary — comprehensible input for acquisition, output for noticing and gap-filling
Genuine Interaction
Real communication creates acquisition conditions that simulated exercises don't replicate
Ideal L2 Self
Most powerful motivational driver — help students envision themselves as competent users
Teacher Tip
“Ask every student: 'Imagine yourself in 2 years, using English really fluently. What are you doing? Where are you?' Make the vision specific and vivid. This activation of the Ideal L2 Self is not fluffy — it's the single most research-supported motivational intervention available to language teachers.”
Frequently Asked Questions
Does SLA research support or challenge grammar teaching?
It supports a limited, intelligent version of explicit grammar instruction alongside communicative practice. It challenges the 'grammar-translation' paradigm as the primary teaching method. The research consensus: grammar teaching accelerates accuracy but doesn't substitute for rich input and output.
What's the best way to create genuine interaction in a private lesson?
Tasks with genuine information asymmetry: you know something the student doesn't, or vice versa. Role plays with genuine decisions. Sharing real opinions on real topics. The interaction must have an actual communicative purpose, not just simulate one.
How much of the lesson should be input vs. output?
No fixed ratio is universally prescribed, but most practitioners recommend roughly 40-60% student production in a communicative lesson. Lower-level students need more input exposure; higher-level students benefit from more output challenge.