“Acquisition requires meaningful interaction in the target language – natural communication – in which speakers are concerned not with the form of their utterances but with the messages they are conveying and understanding.”
Stephen Krashen
REFERENCE
SHÜTZ, Ricardo. Stephen Krashen’s Theory of Second Language Acquisition. April 1998. Available on: <https://www.sk.com.br/sk-krash.html> Access on Nov 24th, 2018.
Krashen's Second Language Acquisition Theory 