What is the key principle of the input hypothesis?

The key principle of the input hypothesis, proposed by Stephen Krashen, emphasizes that effective language acquisition occurs when learners are exposed to language input that is slightly beyond their current levels of competency. This input is often described using the term "i+1," where "i" represents the learner's current knowledge and "+1" indicates the next stage of complexity or understanding. By providing information that challenges learners just above their existing ability, they are encouraged to stretch their comprehension and gradually acquire new language skills.

This principle underscores the importance of providing comprehensible input that is not too overwhelming, allowing students to gradually assimilate new vocabulary, structures, and forms in a supportive environment. In contrast, options that suggest learning needs to occur at the learner's current ability level or that grammar rules should be taught explicitly do not align with the core tenets of the input hypothesis, which prioritizes meaningful engagement with language. Concepts advocating for completely unconscious learning may overlook the necessity of structured input that facilitates natural language development within a framework of gradual progression.