The Natural Approach is a method for beginners based on observation and interpretation on how a person acquires his first language. It emphasizes on communication rather than on grammar.
One of the things which is very important and conclusive when learning is that the input has to be comprehensible. That is at least what Krashen has always said. Teach with a lot of comprehensible input that will allow the student to activate the acquisition process.
But I also think that even if the input is not comprehensible you end up learning because some kind of unconscious learning. I mean if you spend a lot of time listening to a language (in the country) in the beginning all the input is not comprehensible but you sort of learn something, the accent, the intonation, some isolated words, sometimes some information which is linked with non verbal communication and so on and so forth.