Yes, I can tell from experience.
Learning English is a process of making milage. I read, and read, and read, and even though first I understand just the basic things, and miss out on the more subtle meaning and foreign terms, the longer I read and listen to the language I want to learn, the better I someday will be.
In fact, if you ask me certain words, I wouldn't know the exact translation, but if I read or listen in a context, I understand. Also, when I speak myself, I use terms that come to my mind in such rapid pace that I do not think of them, or question them for their correctness, but have heard the same sequence many times before, so that my memory steps in, before I even have time to think.
If you are together with native speakers they will correct you when you misuse a sequence of expression, or you can see it in their faces, when they look irritated. Then you realize your mistake. Hard online though, through written language, but even there you can notice if someone translates from his tongue literally into English, or if he talks like a native.
I like to see myself as someone who is still learning English, and not as someone who really knows about it. Because that way if I make a mistake or don't understand something, I can say "I'm just learning", and avoid getting irritated. Although I know it doesn't really change too much. Deep down it irritates me. Haha.
I'm joking.
This happens to me a lot. Sometimes I find that although I can understand perfectly well what someone says, I can't find the words to translate it. Understanding something is not the same as being able to translate it. At least not literally.
Maybe one day I will have the experience of speaking directly with native speakers and thus improve my proficiency.
Meanwhile I welcome any kind of feedback, correction, etc. :)