Many recent empirical studies show that language use shapes human thoughts, but studies of behavior and consciousness do not discuss language.
Most inner speech relies on the same brain regions as surface language. When vocalized, the inner speech becomes flesh and blood, echoed cultivated in yourself.
Here’s the formula for any learning. (A) Connection to yourself x (B) Iteration x (C) Continuation. How connected, how iterative matters most.
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.