Language is a behavioural habit. Learning another language is like learning some of the behavioural habits of another culture. If you do not notice these habits you cannot learn them or acquire them.
If you talk too loud, or always eat with your mouth open, the first step towards changing this habit, is to notice that you behave this way, and that others behave differently.
Even the first time it is pointed out, may not be enough to get you to notice it that you do it, let alone change it. You will probably continue speaking too loudly or eating with your mouth open. However, as you start to notice that you do this, you can in time train yourself to change your habit.
Language learning is a little like that. You need to notice what is happening in a new language, in order to acquire these new language habits, assuming you want to.
