In my experience, there are 3 stages involved in going from the point where you sort of understand to being able to use something in a language. You don’t have as much control as you might think and schools and teachers usually have even less.
We could analyze this stuff much deeper, but I find this to be the easy way to break it down. We progress through these stages by encountering these words/expressions/sentences in real life (read/heard/tried to use). Spaced repitition will significantly increase the chance of the words in question staying in your short term memory indefinitely so that when you encounter a situation where it is used…you can remember/use/understand it.
- Able to understand the underlying meaning of the question and possibly able to offer a simple answer such as in the case of กินข้าวรึยัง – กินแล้ว or “have you eaten yet?” — “ate already” but unable to reproduce the original question or even work out for certain the words involved. It is still just a string of sounds which one can’t distinguish between or repeat with any accuracy, but somehow by having heard it over and over, you know what they are asking you.
- Able to understand the entire meaning and can now pick up most of the words in the sentence and answer properly, but still unlikely to be able to produce the actual question correctly.
- After having heard the sentence countless times, with varied repetition, we reach a stage where we can completely understand the question in most if not all of its forms and can now reproduce it naturally (or close to it) as we have heard it used naturally repeatedly for some time now.