I learned a lot from learning a second language. I started learning Japanese on my own and moved to Japan several years ago. I now work at a Japanese company where I spend most of my day speaking and writing Japanese.
Most people think about learning a second language as a kind of rote learning. You memorize the vocabulary and grammar of a language and when the time comes to use it, you recall the vocabulary and grammar from your memory and use what you remembered to form a coherent thought or sentence. You do this in the same way to deconstruct things that other people say. Many language learning methods focus on this aspect of learning a language. Spaced Repetition is one of them and is an extremely good way of remembering vocabulary and facts.
However, after interacting with many people living in Japan and attempting to learn the language, I felt that too many people focus on this area too much. Their knowledge of the language constructs, vocabulary and culture sometimes exceeds my own, but their fluency in conversation leaves something to be desired. How is that?
I’ve come to believe that learning a language is as much about muscle memory as about rote learning. Speaking a language is a real time activity. You need to be able to respond to a query, ideally, in about a second, and absolutely within a few seconds. Getting that kind of speed requires practice. You need to be able to understand commonly used phrases quickly, and react properly when you don’t know how to respond. The only way to really get better at conversation is to talk to people. The more the better.