There comes a moment, when you put together a 1000-piece jigsaw puzzle, that you can make out the picture. It looks more like the picture on the box front and less like an amorphous jumble. That happens when studying a language. There comes a moment when you understand more than you don’t. That’s a joyous day.
When does that day come? Somewhere after piece 500. In the meantime, you are painstakingly learning vocab and grammar, one piece at a time (the day’s lesson). It can be arduous and despairing (“when will I ever learn this language???”). But just as in the jigsaw puzzle as with the language, all advance from that day on is downhill. It’s fun, a mad rush towards total fluency, the satisfaction of snapping in the last piece and admiring your work. Congratulations, you’re bilingual.
I imagine that moment happens for math and science too! (I must admit, I don’t know if the light ever fully came on for me as a student in these studies).