Linguist Stephen Krashen believes that people who have already learned a language fluently would be more successful in learning a new language if they would approach the learning process like children naturally do.  In other words, if they would simply immerse themselves in the new language, express themselves without worrying about making mistakes, and keep communicating as best they can until they can sort out the language “nuances” through the language “data” they receive from listening to it in various contexts AND from others’ responses to what they say.   The brain needs time to distinguish between meaningful units of sounds they aren’t in one’s native language, to identify common language structures and words/phrases used in various contexts, and to essentially create meaning from the massive amounts material it has to process and sort into a coherant message.   The process of recognizing patterns of speech, attributing the meaning behind guestures and other forms of unspoken communication, and the various sound-symbol relationships required for reading and writing takes time.  Krashen believes that focusing on the “form” of language (grammar) rather than on its “function”  (usage) delays language learning because it inhibits language learners from speaking until they’re “ready” and, thus, limits the amount of time they would otherwise have to practice using it and learning as they go–like children do when they are acquiring their first and even additional languages.

For a more detailed explanation of his theory of language acquisition, open the link to his article below.

Source: Stephen Krashen’s Language Learning Theory