Comprehensible Input is a term devised by Stephen Krashen (2009). He explained that for students to acquire a new language, they must be exposed to the language in simplified terms that they can understand. According to the British Council website, comprehensible input is language input that can be understood by learners despite them not understanding all the words and structures in it. According to Krashen’s theory of language acquisition, giving learners this kind of input helps them acquire language naturally, rather than to learn it consciously (Krashen 2004). Krashen offers the formula i + 1 to explain comprehensible input where i represents a student’s current level of proficiency and +1 represents input that is just slightly above that level. He also believes that acquired language and literacy are both developed by understanding messages and not by memorizing grammar rules and vocabulary.
Comprehensible input is so important that it has been identified as one of the 8 essential features in planning and delivering effective lessons for ELLs in the well-researched and implemented Sheltered Instruction Observation Protocol, or SIOP Model, an approach for integrating the teaching of content and language in classrooms with ELLs (Echevarria, Vogt & Short, 2017).
Importance in the classroom?
“the defining characteristic of a good teacher is someone who can make input comprehensible to a non-native speaker, regardless of his or her level of competence in the target language” (Krashen, 2009)