“Back in the day,” musicians learned the vocabulary of improvised music by playing along with the recording, maybe hundreds of times, learning the melodies and improvised solos. Such musicians became fluent, geniuses even, despite (in some cases) not being able to read a note of music. Music is its own language, with notation an effort to communicate it in non-sonic form – but, music is (according to the late Milt Jackson) sound and feeling.
Transcription is an essential skill for all musicians who want to progress in deeper understanding of what they’re supposed to be playing, and how music “works.”
Transcription takes you “inside” the music in a more profound and engaging way than passive listening – although, after doing enough transcription, you learn “analytical listening” enabling you to “know what it is” when you hear it, even as you do “recreational” listening.
Improvisation is, essentially, ornamentation of melody, or ornamentation of harmonic structure, in a rhythmic context.
It’s like a puzzle to be solved. Progression of the “chords” (harmonic environments), presents harmonic challenges which the improviser navigates, much like a kayaker shooting the rapids on a river. It’s much easier to “learn the river” after following somebody who’s been through it before – and the more you do it, the better you get at it.
And, you’ll be better equipped to learn tunes quickly, and possibly supplement your musical income with transcription and arranging services for those who can’t or don’t want to do it themselves!