• Katie Welch, Ph.D.

Input & Output in Language Development

Updated: Jul 3, 2019

One of the most fundamental concepts that language teachers, and especially ESL teachers, need to understand is the difference between input and output. Much ink has been spilled as to whether input alone can account for the language acquisition process or if output is necessary as well. While learning the history of Stephen Krashen’s Monitor Model, Swain’s Output Hypothesis, and Long’s Interaction Hypothesis helps us understand the ongoing debates in this area, on a practical level, it’s important to note that most K-12 curriculum tends to assume that opportunities for both input and output are necessary in a classroom to produce a competent language learner. As an example, Total Physical response (TPR) – a 1980s method that heavily prioritized input only – has been rebranded as one strategy amongst many that facilitate language learning. TPR is simply a tool in the ESL teacher’s arsenal instead of the be-all-end-all it once was.


The English Language Proficiency Standards that govern ESL curriculum in the state of Texas are similar to many other state standards in that they assume proficiency in both input and output. Section 74.4(a),4) states. “Effective instruction in second language acquisition involves giving ELLs opportunities to listen, speak, read, and write at their current levels of English development while gradually increasing the linguistic complexity of the English they read and hear, and are expected to speak and write. While this document doesn’t use the actual terms input and output, they are embedded in the structure of the second half of that sentence. First, it mentions reading and hearing. That’s input. Then, it mentions speaking and writing. That’s output.


Some of the prominent voices in the ESL community have begun to use the term SWiRLing to as an acronym to refer to the four domains of language development:


S - Speaking

W - Writing

i - Interaction

R - Reading

L - Listening


The mid-letter “i” in the acronym is a reference to interaction, an essential component of any ESL classroom that requires both input and output. While the acronym isn’t organized by in/output, the fact that all four are present is another nod to the need for both aspects—input and output—in language development.



Although input and output are generally terms used when talking about second language acquisition, the same concepts are also present in first language acquisition discourses. When talking about a child learning his or her first language, we often see the terms receptive language and expressive language.


Receptive language is the language that we receive from others with no expectation to produce anything on our own. This happens as we listen to our moms or dads or other family members talking to us and to each other. We hear the stream of sounds they are making, internalize which sounds comprise our own native language (and hence are the ones we need to attend to), and then ultimately discover word boundaries, syntax, and the like. As with children learning a first language, we expect second language learners to generally possess higher receptive language than expressive language. This phenomenon is exemplified when you hear a learner say, “I can understand more than I can say.” Expressive language is the knowing-how-to-respond piece. It’s the language that a learner actually produces—the spoken and written words that they express.


Being conversant about receptive and expressive language is not only useful for teachers of English learners, but also for any teacher working in early childhood or elementary classrooms. It also has the added benefit of enabling you to speak more knowledgeably with your campus Speech Language Pathologist.


Below is a visual that helps graphically explain the way these four domain of language development align with the concepts of input/output and productive/expressive language. A downloadable high-resolution PDF version is also available at no cost at the linguistics4teacher store.



Whether we call it input, output, receptive language, expressive language, or SWiRLing, the bottom line is this: at times, language learners will be quietly taking in the language around them and at other times will be creating it – either orally or through the written word. Our job as teachers is to facilitate opportunities to do all this and more, in every lesson every day and in the most interactive way possible.

© 2020 by Welch Education, Dallas, TX