@Update: 10,000 Sentences is Dead. Let the MCD Revolution Begin! | AJATT | All Japanese All The Time is.gd/AWLzAv
OK…this is embarassing to admit, but: I didn’t invent this method of learning language. A couple of very sharp Poles learning English did. And a very sharp American linguistics professor says they’re right. I merely put two and two together and applied it to Japanese.
Theirs is the hypothesis that input (reading, listening) matters more than output (writing, speaking), and that input of high quality and quantity naturally leads to high quality output, without much effort. In English, that means stop talking before you hurt yourself.
When you learn sentences in Japanese, do not force yourself to use them. Don’t try to remember them in order to say them. It’s too hard, and too failure prone AND, if you say the wrong thing, you might start building a bad habit, and on top of that, there might not be anyone there to correct you. Ever notice those people who live in an English-speaking country for 30 years but still don’t speak grammatically? That’s what happens when you force output too early. When the time comes for you to use those sentences, you’ll know. You won’t have to think or “work” at it as such; you won’t have to rack your brain. They’ll just come to you. Like when you’ve seen a movie so many times that you start to know all the dialogue.
So keep watching, keep listening, keep reading, keep observing. If your output worries you, then just watch, listen to and read even more. Don’t worry that you understand so much more than you can independently reproduce, that’s only natural.
For further reading, I refer you the following sterling pages. Tell them Khatzumoto sent you.