““Third, the Comprehension Hypothesis, on which Krashen’s concept of sheltering is based, holds that input is what matters in second language acquisition—not output. As noted above, forcing students to “produce” a second language can be counterproductive. Output per se does not contribute directly to language acquisition, and forcing speech before students have acquired enough language to express their meaning tends to create anxiety and embarrassment, thereby raising the “affective filter” that keeps input from getting through.””
