Learning a language is physical exercise. To speak is to change sounds by breathing out. It’s very much like sports or musical performance; you must acquire how to breathe, keep posture, and move muscles.
Japanese and English have very different phonologies, meaning that you can’t use your body the same way to speak each language. You have to learn how to move your jaws, make air noises with your tongue and mouth, and make sounds in the back of your throat.
The basis of learning English is to practice its physical movement. Not only speaking or listening but also reading and writing are included in this. And we acquired our native languages without effort that way. It’s essential to move your body and set up an opportunity to practice rather than “just studying.”