Making Input Count: The Power of Comprehensible Input in Language Teaching

Silvia Bastow
Jul 12
7 min read

This academic year has been an incredibly full and rewarding one for me, filled with opportunities to speak at conferences locally, nationally and internationally; to work with and deliver CPD across a range of schools and Trusts; to develop content; to write two books; and to navigate an Ofsted inspection, among many other things.

As the year draws to a close, I wanted to dedicate my final post to a topic that has come up repeatedly in my conversations with colleagues and through the research I’ve been doing this year: Comprehensible Input. It’s an area I’ve been exploring in more depth, both in theory and in classroom practice, so I’d like to share some reflections on what I’ve learned.

More and more language teachers are becoming aware of and applying the principles of comprehensible input (CI) in their classrooms: a shift that has been reshaping language teaching practice worldwide. Originally introduced by linguist, Professor Stephen Krashen, comprehensible input refers to language that learners can understand even if they don’t yet know every word or structure. By being exposed to language that is just beyond their current level of understanding, often referred to as “i+1”, learners are able to infer meaning from context, making it possible for them to acquire new language naturally and effectively.

This post explores the importance of comprehensible input in modern language teaching and outlines some strategies for effectively implementing it in the classroom context. I believe this approach can not only support more natural learning but also increase motivation, engagement and long-term retention.

Stephen D. Krashen - American linguist, educational researcher, Emeritus Professor

Why Comprehensible Input matters

Comprehensible input is crucial because it mirrors the natural process of first language acquisition. Children don’t learn by memorising verb tables or parsing complex grammar; they acquire language by being surrounded by speech that they can make sense of, gradually building vocabulary and grammatical understanding over time.

Realistically, we may not be able to fully replicate these conditions in a school setting, given the limited curriculum time and the fundamental differences in how we acquire additional languages compared to our first. Unlike learning our mother tongue as toddlers, where we're immersed in it 24/7, second, third, or even fourth languages are typically learned in more structured environments (in the school or by attending language courses).

However, second language learners can still benefit greatly from exposure to input that they can decode using contextual clues.

One of the most compelling reasons this approach works is its alignment with Lev Vygotsky’s concept of the zone of proximal development (ZPD). This zone represents the sweet spot between what learners can do independently and what they can achieve with guidance. Comprehensible input keeps learners in this productive space, stretching their abilities just enough to challenge them, but not so much that it causes frustration or disengagement.

What the Research says

Krashen’s Input Hypothesis has long argued that acquisition, not just learning, is what ultimately leads to language fluency and that acquisition happens when learners receive enough input that is both understandable and meaningful. While some critics point out that his model downplays the role of output or grammar instruction, more recent research from the likes of Paul Nation and Bill VanPatten supports a balanced approach, with meaning-focused input being one of the key strands in effective language learning.

Nation’s Four Strands framework, comprising meaning-focused input, meaning-focused output, language-focused learning and fluency development, emphasises that around 25% of class time should be devoted to input that is both accessible and engaging. His work also highlights the importance of repeated exposure to high-frequency vocabulary in varied contexts, something that comprehensible input naturally facilitates.

Find out more about Nation's 'Word frequency and vocabulary learning in my post here.

Global School-Based applications

Comprehensible input isn’t just a theoretical ideal, it’s being used, successfully, in classrooms around the world. Here are a few real-life examples that demonstrate its power:

Germany: Story Listening in Secondary MFL

At a conference I attended last year, colleagues shared that in some secondary schools in Hamburg, MFL teachers use a modified version of Story Listening (a technique inspired by Beniko Mason) in their French and Spanish classrooms. Each week, the teacher tells a short story supported by drawings, gestures and occasional L1 translations. Students then complete low-stakes follow-up tasks such as drawing scenes, sequencing events, or acting out parts of the story. Over time, learners begin to absorb vocabulary and grammar naturally. One teacher observed that even lower-attaining students started producing more complex sentences spontaneously after regular exposure to this approach.

UK: Graded Readers in KS3 German and French

There are language deparrtments in England that are championing the use of graded readers - short books written in accessible language with high-frequency vocabulary. Schools using these readers (often created by teachers themselves) report increased motivation, better vocabulary retention, and stronger reading confidence. Paired with audio versions, these readers can provide excellent listening and reading input. Some schools have even implemented “Drop Everything and Read” sessions for languages, echoing whole-school literacy drives.

USA: Comprehensible Input-Based Curricula

In the United States, particularly in states like Oregon, Texas and California (as I have been told), teachers are implementing full curricula based on comprehensible input. Textbook use is minimal. Instead, teachers use movie talks, personalised questions and answers (PQA), and extensive reading programmes to immerse students in the target language from day one. These teachers often report higher engagement and lower attrition, especially among learners who previously found languages intimidating. This is something I would like to research more, so if you are one of my blog readers from USA, do get in touch, please.

Australia: CI in Primary Schools

In some Australian primary schools, CI-based approaches are embedded in daily routines. Teachers use songs, routines, puppets, and games to make language accessible and fun. The goal isn’t to produce grammatically perfect speech, but to ensure students can understand and enjoy the language. Again, if you are one of my blog readers from Australia and you use this kind of approach, I would love to know more, please.

Strategies for Implementing Comprehensible Input

So, how can we bring more comprehensible input into our own Language classrooms, whether we’re working with Year 3 or Year 13?

Using visual aids: Visual aids such as pictures, videos and realia (real-world objects) can make language input more understandable. For example, when teaching vocabulary related to food, showing images or using a cooking demonstration video can help students infer meanings from context. Additionally, gestures and body language can reinforce spoken language, aiding comprehension.
Simplifying language without dumbing down: Teachers should speak clearly and at a moderate pace, using high-frequency vocabulary and simple sentence structures and recycling them often. This does not mean oversimplifying the content but rather making it accessible. For instance, when introducing new vocabulary, use familiar words and phrases to provide context, gradually increasing complexity as students become more comfortable.
Scaffolding instruction: Building on students' prior knowledge helps them connect new information to what they already know. Providing sentence frames and starters can also support learners in constructing sentences, allowing them to express themselves more easily. For example, using sentence starters like "I like ... because ..."
- Ich mag …, weil …
- Je préfère … parce que …
- Me gusta … porque …
can help students practise new verbs within a familiar structure. These structures allow students to express meaningful thoughts while staying within their comfort zone.
Contextualising language learning: Real-life scenarios and storytelling can make language learning more relevant and engaging. Designing activities around everyday situations, such as ordering food in a restaurant or asking for directions, allows students to practise. In my previous post I have explored TPRS as another way of introducing vocabulary and new language. Read the full post here.
Offering extensive reading: Free voluntary reading, even for just 10 minutes a week, can boost vocabulary, comprehension and motivation. Providing a library of short, levelled readers. Letting students choose what they want to read. Pairing it with light activities like drawing a scene or summarising in English or the TL.
Embracing repetition: Not being afraid to repeat stories, songs, or activities. Repetition with variation is key to retention. For example, revisiting a story with new illustrations, a different ending or from another character’s perspective.

Balancing Comprehensible Input with Curriculum Demands

Let’s be real - many of us teach in systems that still prize grammar-based exams, controlled assessment and measurable output. So how do we reconcile comprehensible input approaches mentioned above with these expectations?

Here are some observations:

CI and grammar are not enemies. Once learners have acquired a foundation of natural language through exposure, they tend to be more open to explicit grammar instruction. I see grammar as the fine-tuning, not the engine of language learning, but still an essential component. At a certain point, explicit teaching becomes necessary. As a linguist fluent in four languages, I know from personal experience that I couldn’t fully grasp a language without understanding how it works. For roles that demand a high level of language proficiency, it's crucial to use language accurately, including its grammar. In my view, this can’t be achieved through implicit learning alone, which is exactly why we all attend school to learn to speak and write accurately in our own language, too.
CI can be exam-relevant. Choosing stories and contexts that match your curriculum themes: holidays, health, technology, school. Students learn the same content - just in a way that sticks.
Even 10 minutes a day makes a difference. You don’t need to overhaul everything. You could start with a “CI starter” each lesson - a mini story, a question, a song and build from there.

Final Thoughts: Comprehensible input is a mindset

For me, comprehensible input isn’t just a technique - it’s a mindset. It’s about trusting that our students are capable of acquiring language more naturally when we give them the right conditions: exposure, meaning, support and space.

It means shifting our role from instructor (teacher) to language guide - pointing out patterns, telling stories, asking questions and celebrating growth.

Balance is all!

Above all, it’s about making language learning joyful again.