Language Acquisition is the process in which a child acquires the capacity to comprehend language. Language acquisition is the process in which a child learns his mother tongue. When language is learned without any practice and with the help of surroundings, it is known as language acquisition.In Theory of Second Language Acquisition, Stephen Krashen proposed the five main hypotheses, the input hypothesis is one of them.According to the Input hypothesis, comprehensible input refers to the input slightly above the learner's current level of mastery.It helps learners in language learning by making them able to communicate efficiently, acquire language naturally and understand the text effectively.Language is acquired not when the input is repeated several times, but when that input is understood, when the learner understands what it means and can make use of it. Hence, it is clear that the term 'comprehensible' input in language is proposed by Stephen Krashen.Additional InformationAccording to Vygotsky, the most important part of language learning is "Social interaction".Chomsky emphasizes that 'children have an innate universal grammar' which helps them in acquiring and understanding grammar regardless of where or how they are raised.