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Input Vs Output Hypotheses

Comparative Analysis of Krashen’s Input Hypothesis and Swain’s Output Hypothesis

The field of second language acquisition (SLA) is characterized by diverse theories that aim to explain how individuals learn a new language. Among these, Stephen Krashen’s Input Hypothesis and Merrill Swain’s Output Hypothesis stand out for their influential perspectives on the roles of comprehension and production in language learning. This article presents a comparative analysis of these hypotheses, highlighting their key features, differences, and implications for language teaching, culminating in a synthesis of their applications in real classroom settings.

Key Features

Feature Krashen’s Input Hypothesis Swain’s Output Hypothesis
Main Focus Comprehensible input (i+1) Language production (speaking and writing)
Learning Mechanism Language is acquired through understanding input just beyond the current level of competence Language is acquired through the process of producing language, which triggers cognitive mechanisms that facilitate learning
Role of Consciousness Emphasizes unconscious acquisition through exposure Highlights the role of conscious effort in noticing gaps and hypothesis testing during language production
Feedback Implicit within the input Explicit feedback on output is crucial
Practical Application Extensive reading, listening to native speakers Speaking and writing tasks that encourage active language use

Comparative Analysis

  • Focus on Language Acquisition: Krashen’s Input Hypothesis (1982) argues that language acquisition occurs when learners are exposed to language that is slightly above their current level, emphasizing the importance of understanding language input. In contrast, Swain’s Output Hypothesis (1985) posits that language production is not merely a practice of what has been learned but a fundamental part of the learning process itself, facilitating deeper linguistic processing and learning.
  • Learning Processes: Krashen suggests that acquisition happens naturally and unconsciously through exposure to comprehensible input, with minimal emphasis on feedback. Swain, however, sees language production as a conscious process where learners notice gaps in their language knowledge, which prompts internal learning processes.
  • Role of Feedback: In Krashen’s framework, feedback is less emphasized and is considered implicit within the input. Swain’s approach, however, underlines the importance of explicit feedback on the learner’s output, which helps learners refine their language use and understanding.

Synthesis and Application in Language Classrooms

Integrating Krashen’s and Swain’s hypotheses in the language classroom involves creating an environment where learners are exposed to both comprehensible input and opportunities for meaningful language production. Here’s how these theories can be synthesized and applied:

  • Balanced Approach: A curriculum that balances activities focusing on input (e.g., listening and reading) with those requiring output (e.g., speaking and writing) can cater to the comprehensive needs of language learners. This approach ensures that learners not only understand the language but also can use it actively.
  • Real Classroom Setting Example:
    • Input-Focused Activity: Implement an extensive reading program where students choose books at their level +1. This could be supplemented with listening exercises using podcasts or videos on topics of interest to the students, ensuring the content is just beyond their current level but still comprehensible.
    • Output-Focused Activity: Organize debates or presentations on topics covered in the reading and listening materials. This requires students to actively use the language, promoting hypothesis testing and metalinguistic reflection as they prepare their arguments or presentations. Feedback from teachers and peers during these activities helps address the gaps in learners’ language use.
  • Feedback Integration: Incorporate structured feedback sessions where students reflect on their output, discussing the challenges they faced and how they attempted to overcome them. This can be done through peer reviews, teacher comments, or self-assessment exercises.
  • Technological Tools: Utilize language learning apps that offer adaptive learning paths, providing both input at the right level of challenge and interactive exercises that require output. These tools can offer immediate feedback, aligning with Swain’s emphasis on the importance of feedback in the learning process.


Krashen’s Input Hypothesis and Swain’s Output Hypothesis offer valuable insights into the language acquisition process, emphasizing the importance of both comprehensible input and meaningful language production. By integrating these perspectives, language educators can create a dynamic and effective learning environment that supports all aspects of language acquisition. This balanced approach, supported by real-world examples and strategic feedback mechanisms, ensures that learners not only understand the language but are also able to use it confidently and competently.


  • Krashen, S. (1982). Principles and Practice in Second Language Acquisition. Pergamon Press.
  • Swain, M. (1985). “Communicative Competence: Some Roles of Comprehensible Input and Comprehensible