Fluency comes through immersive listening.
We became fluent in our first language through hearing people speak it – our families spoke around us and to us from before we were born. It was through that repetitive listening that we developed the scaffolding of how the language works, until we were able to speak. (Non-hearing people go through a similar immersive experience, using another sense to rack up hours experiencing their language.)
Music is just the same. You’ll never be fluent without immersive listening. Most of this immersion happens almost passively – we aren’t listening to learn, we’re listening for personal interest, for distraction, or because it’s just on in the background. But each hour of listening helps build the understanding we need to speak fluently. It doesn’t matter the genre – all types of music require this immersion.
This is a primary barrier to academic musicians. They think they can learn to speak this language in the classroom. And while they can acquire the tools, those tools are nothing without the fluency they will gain from listening.