Free conversation is a great integral part to improving and maintaining skill in a language, but I think many learners, especially advanced learners, will eventually feel something is missing.

In my role as an online teacher, I meet many learners who already have some competence speaking English, and who do not have a specific goal (such as achieving a test score or passing an interview) but who wish to continue to study, or find ways to practice the English skill they have, so they don't lose it. Of course everyone likes the idea of improving a little even if it isn't a priority.

When I talk in English with a competent communicator, I think of it a bit like playing weekend basketball or soccer at the park. They just want to have fun, get some exercise and maybe keep some basic game skills. Some people might practice on their own and will perform better, but most will see their level just maintain or decline over time.

There are some differences with language though. When you play games you kind of know your level in the outcome. In conversation there isn't a score and there isn't a clear pass-fail. It can be really hard, and frustrating, to self-assess your own improvement or decline through conversation. Most of us who speak multiple languages have gone through some difficult processes to do so. We know it was hard and we don't want to have to start over or throw away what we have. We may also be a bit tired of the more difficult study processes, so we are reluctant to 'study' in the traditional sense.

Unfortunately, the same way that your body discards unused muscle and aerobic ability when you don't exercise, unused knowledge and skill do decline without use (not as fast as muscle though, thank goodness). Our natural inclination is to be efficient. We conserve energy for what really matters by giving as little energy and effort to what isn't being used or isn't important RIGHT NOW. If you don't use your stomach, you won't have a six pack and your stomach will swell up with fat just in case you run out of food. If you don't use a language, it declines.

You need to tell your brain that your desired English level is important. Having casual English conversations will help to an extent, but if your level is above that, you will decline. This message to your brain can't be sent by text or memo. The brain and body respond to effort/actions and emotional response to input (also known as focus). This latter is most important.

input + emotions. FOCUS
Imagine you are sitting on a park bench and overhear two strangers having a conversation. You don't know them and you don't care about what they are saying. You hear it. In the conversation they mention someone's name. Later that day you are home and overhear a conversation or phone-call between two loved ones. A sibling, a child, a parent, think of any two people you love and care about, who matter to you, having a conversation. They talk about a new love interest, a date, a name is mentioned about this new person in their/your lives. The conversation is the same length roughly as the strangers at the park. A month goes by. Are you going to remember the conversations and names mentioned in the boring strangers' conversation, or the conversation of your loved ones?

You remember what matters. Emotions govern memory, not repetition. Repetition helps a lot, but it's a poor substitute (and it's boring). Think about things that were said to you that hurt or that made you happy. An insult, a compliment, a proposal, life changing news. We all have memories of single words or sentences said to us in a special or difficult moment, things we will never forget, things that were only said once. Focus, caring. This is what governs your memory.

Language learning starts with input. Without input we have nothing to use to try to express our self. We start by hearing new words, new expressions. Our brain does NOT process all input the same!!! Just hearing the languages is not enough. You have to care. You have to make an effort to understand and have a reason to remember. Forgetting things you learned once is also cured the same way- to get the input again. 

So how do we do this with conversation? How do we use this knowledge to help us maintain our level?  The answer is FOCUSED practice. Not JUST free conversation.

FOCUSED practice is about understanding two key factors.
YOUR CURRENT LEVEL
YOUR TARGET LEVEL

Let's go back to the analogy of weekend sports, say basketball. If you set your goal to 90% accuracy on free throws, you can test this very easily and you can practice it as well. shoot 10, see how many go in. If you shoot poorly, you practice.  Simple. If you just play in pick up games and never practice, you know that that ability is going to decline. You won't practice and you won't pay attention to your overall performance in that area.

Knowing your level, testing it, and keeping goals is critical. You can still have free conversation but it won't be free anymore. The basketball player who is practicing free throws will pay attention when they get one in a game, it will matter. They will perform better, try harder and notice deficiencies to work on.

ANY focused practice that includes assessment and goal settings will impact all of your other practice. If you work on your pronunciation you will hear it and notice it when free talking in conversation. Same for grammar, same for new vocabulary, same for any other area you focus on. You don't need to do endless grammar drills or take the eiken every weekend, you just need to keep yourself 'in the zone'.  Give your mind focus and motivation to remember, to care.

Without focus your mind is lazy. It finds a way to complete the conversation the easiest way possible. Bad habits, confusing accent, faulty grammar, limited vocabulary- you can converse with any kind person with all of these problems and still get by. When we talk we just want to converse, the details are lost. In free conversation I don't correct every little quirk in my students' speech, it's rude and it destroys student confidence and motivation. Free conversation is not the time for unfocused spot-check error correction and assessment.

IF you have been practicing a given point, trying out a new word, or a point of pronunciation, these things can be addressed in a free conversation. We can give you feedback on successes and failures in regards to your focus.

Going back to the basketball analogy. If my friend has been working on her freethrows and tells me, I watch her game and can tell her after the game 'you shot X/10' 'good job' or maybe give some advice if there was a habit making her miss. This kind of input is welcome because she is FOCUSED. Because she cares.  If I just grab some random player and give them a bunch of criticism about their freethrow, their dribbling etc. etc. They are going to feel insulted and demotivated. it won't be pleasant.

So, in conclusion, I don't think you need to 'study' in an extreme sense but you will benefit GREATLY with a little focused practice even if your goal is just to maintain your current level. And this focused practice will ENHANCE unfocused practice such as free conversation (which is, for good reason, the most popular and pleasant method of 'study')

Now the KIND of focused practice that is right for you is another topic. It goes back to assessing your level and setting your goals. It's a very individual answer. As always, I'm here to help ;)