Bio
Stephen Krashen (born 1941) is an American linguist, educational researcher, and Professor Emeritus at the University of Southern California. He is best known for developing the Input Hypothesis and the Monitor Model of second language acquisition — among the most influential and debated frameworks in applied linguistics. His core argument: language is acquired, not learned, and acquisition happens automatically through comprehensible input (messages slightly beyond the learner’s current level, the i+1 principle). Krashen also developed the Affective Filter hypothesis, arguing that anxiety and stress block acquisition.
Notable Works
Academic theories:
- Input Hypothesis (i+1) — optimal input is just above current comprehension level
- Monitor Model — five-hypothesis framework for second language acquisition
- Affective Filter Hypothesis — emotional state as a gating mechanism for acquisition
- Acquisition-Learning Distinction — unconscious acquired competence vs. conscious learned knowledge
- Natural Order Hypothesis — grammatical structures are acquired in a predictable sequence
Books:
- Principles and Practice in Second Language Acquisition (1982)
- The Input Hypothesis: Issues and Implications (1985)
- The Power of Reading (1993, 2004)
Related
- Topics: Comprehensible Input . Language Learning
- Areas: Languages . Science