I bet if I asked you to introduce yourself, regardless of your level, you’d sound pretty damn good. I’d ask you about where you’re from, your hobbies, your likes/dislikes, and you are a pro. Then I’d ask you about fusion (nuclear, not DBZ), and you’d freeze. You have a gap in your knowledge. You don’t know about fusion. Shame on you.
But you are lower level. So that’s okay, right? The higher the level you get, the more these gaps go away right. After all, I did say studying Japanese is like Tetris right.
Of course your gaps will be filled in, one at a time. But not in the order you think.
A Japanese person of your age will have filled in the gaps in a completely different way than you ever have.
From baby to adult, their knowledge gaps were filled in standard Japanese order.
From the start of your Japanese, to where you are now, your gaps are filled in based on your 1) needs, 2) interests, 3) perceived standards, 4) and complete randomness of what you see.
You never took Math in a Japanese school. Which means that there is a chance that you will never ever run into phrases like Pythagorean theorem (ピタゴラスの定理) or the theory of relativity (相対性理論).
I’m pretty good at Japanese… I can talk about advanced subjects like technology, politics, and law. I’m an adult.
But guess what. Put me in the room with a 6 year old. What does that 6 year old like? Dinosaurs. Even at my level, I would be at a lack for a lot of words. I don’t know the name of most of the dinosaurs that you all know in English that you learned as a child.
Yeah, there is a chance that I will see some TV special on dinosaurs in the future. Or maybe a movie will come out about dinosaurs. Maybe I’ll even watch Jurassic park dubbed. But for now I have a gap in knowledge. And I’m fine with that. You can’t learn everything. You can’t catch them all.
These gaps aren’t just connected because of a foreign language. People grow up in nonstandard environments, in nonstandard ways. People get older and they forget, and stop caring. Memory is finite, and focuses on what you want and need.
So where am I going with this?
You will have gaps in your knowledge, and that’s perfectly fine. Yeah, it sucks when you are in a situation where you are fully fluent in Japanese, having a conversation like a normal Japanese adult, and then suddenly a gap appears that causes you to falter a bit. But, there is a good chance that this will happen even in your own language. Just say you don’t know. There is nothing wrong with not knowing.