4 – Output Theory

We acquire language as we produce comprehensible output.

John Wooden was one of the most successful coaches of all time. During his time at UCLA, he coached his teams to 10 national basketball championships. During one period, his team won 88 consecutive games. But Wooden didn’t mainly focus on winning games. He focused on coaching people — helping them to grow. He was a coach, a teacher, and a philosopher of life. And he is famous for many wise sayings, or “woodenisms.” Here is one:

Whatever you do in life, surround yourself with smart people who’ll argue with you.” — John Wooden

This saying reminds us that when people argue, they sharpen each other’s ideas. In applied linguistics, Stephen Krashen has created a lot of arguments. His bold ideas have made many smart scholars debate and argue, and this has helped bring much progress in second language education.

For example, Krashen (1985) claims that human acquire language by input alone — and output does not help us acquire language. Krashen calls this the Input Hypothesis. (In Elemental Linguistics, we call this Input Theory.) However, Swain (1985) observed language learners who received a lot of comprehensible input, but they failed to attain high levels of grammatical accuracy.

With this problem in mind, Swain suggested the Comprehensible Output Hypothesis. (In Elemental Linguistics, we call this Output Theory.) Learners produce output in speech or writing. Sometimes listeners and readers understand this output. And sometimes they do not understand it.

Now, for example, a learner speaks and notices that a listener cannot understand. At this point, the learner notices a mistake or gap in his language output. Next he tries to modify his output so that the listener can understand. And in this process, he learns something new about the language.

This is the process of Output Theory. We acquire language when we produce output, causing feedback and opportunities to learn from mistakes. It relates to the principle of trial and error learning, which is called “generation” (Brown, et al. 2014). We learn when we generate an answer, make a mistake, and modify our answer.

But regarding Output Theory, Krashen disagrees. He says that output is rare, and so are opportunities to learn from mistakes. Moreover, when we push students to produce output, we also cause them stress. Krashen calls this stress a “high affective filter,” which blocks input.

Krashen may be right about the centrality of input. We cannot escape input. And we cannot produce output without getting input first. But most scholars and teachers agree that we need both input and output. In later sections, we’ll see how output relates to Interaction Theory and Noticing Theory. But for now, we will focus on this basic teaching principle.

That is, when learners are ready, we can help them acquire language by giving them opportunities for meaningful output. The output will often allow students to receive feedback. And the feedback will help them notice gaps in their ability so they can learn.

For example, let’s look a “Find Someone Who” activity. The teacher gives the students a paper with 15 conversation cues. At first, the students review the following conversation frame. FQ stands for follow up question.

  • Use this cue and start a conversation: give a presentation.
  • Q: Have you ever given a presentation?
  • A: Yes, I have?
  • FQ: Where?

Next, the teacher gives students directions.  “You will walk around the class and ask questions. If your partner says, ‘Yes,’ he or she will sign your paper. If you do not understand each other, you can ask each other these kinds of questions written on the board:

  • I’m sorry. Could you repeat that?
  • Once again, please?
  • Come again?
  • I’m sorry. More slowly please.

As students ask and answer questions, they produce output. And the follow up questions allow for feedback, so that a learner can adjust output if a partner doesn’t understand. Moreover, even though this is a controlled grammar activity, the output is meaningful, so the students are actually communicating. They produce meaningful and comprehensible output. And Output Theory says this will help them acquire language.


Dr. Joseph Poulshock

Dr. Joseph Poulshock works as Professor of English Linguistics in the Faculty of International Communication at Senshu University.