output means put out language.. it means language comes out of you.. output can start with gestures and mumbles that show you understand the language input.. the more input you get, the more you can output real words in the language you are learning..

[edit] from the heart

when you play with stories, little by little langauge output just falls out of your mouth, naturally.. you don't think about grammar rules or perfect speech.. instead, you are part of a story that you understand and care about, so sooner or later language will out of you, fluently.. you get a feeling for language..