It 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. Error correction and explicit teaching of rules are not relevant to it, but caretakers and native speakers can modify their utterances addressed to acquirers to help them understand, and these modifications are thought to help the process (KRASHEN, 1981).

Which process is Krashen (1981) stating about?