Comprehensible Input and Language Learning

What is comprehensible input?

The idea of comprehensible input comes from the linguist Stephen Krashen. In his 1982 book Principles and Practice in Second Language Acquisition, he argued that learners reach the next level by understanding messages that are “a little beyond” where they are now, with help from context and what they already know. [4] The key point is that input just beyond what a learner already knows can still be understood with that help, and understanding it is what leads to acquisition. [4]

What threshold is required for comprehension?

How much of a message needs to be intelligible to a student for the input to be considered “comprehensible”? Studies of English learners estimate that if a student knows about 95% to 98% of the words in a sample of language, they can understand it adequately. [1][2] In a study by Hu and Nation, 15 of 17 readers understood a short story well when they knew every word, but only 6 of 17 when they knew 95%; the authors estimated that most readers need about 98%. [1]

In a 2011 study of 661 learners, comprehension rose steadily with each extra percentage point of known words and did not jump at 95% or 98%. [3] Listening may need less: in a 2013 study, most listeners understood short, informal stories adequately at 90% and well at 95%. [5]

Comprehension may also be enhanced if the learner is exposed to more than just the message itself. For instance, a teacher may use written and spoken text in addition to props, drawings, gestures, intonation, and other methods to help convey meaning. [4]

How do you find input at your level?

Graded readers are one of the best sources of comprehensible input. Graded readers are a type of story designed for language learning, especially for adult learners.

Graded readers are designed to use a core of common vocabulary at a specific level, and then gradually mix in additional vocabulary slightly above that level. [2] Importantly, the new vocabulary is repeated throughout the story, and often explained in footnotes or a glossary.

This allows a reader to encounter and learn new words in context, and then reinforce those words as they continue to read the story. Moreover, graded readers usually explicitly target a specific language proficiency level, so it's not that hard to find a series which matches your level.

Comprehensible input and Second Language

Second Language is heavily inspired by the theory of comprehensible input and the design of graded readers. The fundamental idea of Second Language is to create an engaging game environment where the player feels genuinely invested in the game world, story, and players.

Furthermore, you can imagine the entire progression of the game conceptually like one continuous graded reader story that slowly builds up your language and comprehension. In fact, we make direct use of the footnotes concept, providing footnotes for new vocabulary we introduce in dialogs and other content throughout the game.