Just wanted to say that for now.
Thank you!

Natalie, believe me , no one is being hurt here. As you see, people are enjoying in their L2,L3 etc…

"Ask any exchange student (or my now quad-lingual Sweedish friend): the best way to learn a language is to TALK.. You need to practice putting thoughts in your head into words. (not matter what the result is!) It is proof of what you are really retaining/can use on the fly."

So basically one can talk about things one doesn't know? Is there some kind of language source that we don't know (apart from the brain)?
Also, I am now in a foreign country and I am surrounded by exchange and foreign students, 99%of them were required to have at least intermediate knowledge of language (German) and then they were sent to special preparatory schools to reach C1 level in German. Four months, 5 days/week, 4h/day plus self learning.So you see, that is a lot of daily input.

"At the beginning of my stay in Japan, I tried the input-before-output method (I thought the same: If I can think things in Japanese, I will definitely be able to say them later!), and it failed miserably (MISERABLY!!!)."

So you decided to come to this site to warn others, not to make your mistakes and it is possible to think in a foreign language and not being able to speak. That is something new.
How much input did you put? 10 000 sentences. All Japanese All the Time?

"I only began becoming fluent when I made daily efforts to produce sentences and messages. So what if my grammar was a little off?"

So what is the difference between your method and AJATT? 10 000 sentences, most of them written also with the hand.

"I was always monitoring what I was hearing and saying, and listening to how native speakers word their sentences and use certain words. It didn’t take longer than a week for me to be able to fix a mistake I had been making for the past few months."

Again , explained several times on this site , how to imitate Native speaker.

I don’t speak English perfectly some of the time (everyone makes mistakes; even after being immersed in perfect English nearly my entire life), and I speak Japanese perfectly much less than that; but the point is I am making an effort and in turn making an improvement.

Everyone is making effort. The difference is that with AJATT you don't feel psychologically abused compared to regular classes, grammar drills, output pressure etc… You feel happy and in turn make better progress than "monitoring" obsessed individuals.

Actually, every single person I’ve ever asked who’s learned to speak my L1 (English) fluently has told me they’ve learned it from watching lots of TV. 🙂

The one downside I see is the occasional awkward moment. I was trying to read a Japanese book in a coffee shop recently, and some random guy comes up and asks (in Japanese) if I’m studying Japanese. I understood everything he said *perfectly*, but didn’t know how to answer! I stood there and nodded my head like an idiot. 「uh, はい？」

Ask any exchange student (or my now quad-lingual Sweedish friend): the best way to learn a language is to TALK.. You need to practice putting thoughts in your head into words. (not matter what the result is!) It is proof of what you are really retaining/can use on the fly.
At the beginning of my stay in Japan, I tried the input-before-output method (I thought the same: If I can think things in Japanese, I will definitely be able to say them later!), and it failed miserably (MISERABLY!!!). I only began becoming fluent when I made daily efforts to produce sentences and messages. So what if my grammar was a little off? I was always monitoring what I was hearing and saying, and listening to how native speakers word their sentences and use certain words. It didn’t take longer than a week for me to be able to fix a mistake I had been making for the past few months.

I don’t speak English perfectly some of the time (everyone makes mistakes; even after being immersed in perfect English nearly my entire life), and I speak Japanese perfectly much less than that; but the point is I am making an effort and in turn making an improvement.

ps. I learned the kana before the kanji, and I wouldn’t have had it any other way. There will always be more kanji to learn, but being able to write in kana is a giant step towards being able to fully immerse yourself in Japanese. (being able to write the words you don’t know)