Comprehensible Input (i+1 Hypothesis)
Stephen Krashen's second-language acquisition hypothesis stating that language is acquired when learners receive messages they understand with one step beyond their current level.
A core tenet of the Input Hypothesis in SLA theory proposing that grammatical competence and lexical acquisition develop subconsciously when input contains linguistic structures slightly ahead of the learner's current competence level (denoted as i + 1).
Historical & Empirical Context
Formulated by linguist Stephen Krashen in the late 1970s and 1980s, forming the foundational theoretical basis for communicative and naturalistic language learning methodologies worldwide.
Core Principles & Mechanics
Input must neither be too simplistic (no learning delta) nor excessively complex (cognitive overload and affective filter shutdown).
Explicit learning of grammatical rules rarely converts into spontaneous conversational fluency without massive comprehensible context.
Lowering anxiety, stress, and penalties creates optimal conditions for language processing mechanisms to absorb native patterns.
In Practice
i+1 is a targeting principle: the input should be one step beyond comfort, not ten.
Audit your material: if you understand under 70% of a text, drop a CEFR level rather than heroically grinding.
Pair input with production β read a sentence, then re-type its cloze. Input primes, output cements.
Re-listen to mastered sentences at 1.2x speed; stretched audio keeps known content inside the learning zone.
Frequency-ranked corpora are i+1 made practical: the next sentence usually contains words you've already met.
Frequently Asked Questions
How does ClozeForge implement Comprehensible Input?
ClozeForge structures sentences in strict CEFR frequency order. In every cloze card, 90β95% of the sentence is comprehensible context, with exactly one target word or grammatical node (i+1) requiring active production.
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