My challenge is that my “performance skills” were all honed around beautiful tone, lyric recollection, (melody recollection was generally automatic,) melodic variation attuned to known or heard harmony, and emotional connection to the lyrics and/or music communicated through music tone/timbre, face & body. (Hell, with rehearsal I can dance and sing if I need to…although I get out of breath. I find the “paper guide” to be at odds with creating an emotional connection with the audience.) My “performance skills” had not been honed to include harmony/chord identification or recollection, or finger placement and/or precision on piano or guitar. Hence, I can prepare myself to sing something, and I can improvise vocally (in performance) with a song I’m hearing for the first time. I have limited experience performing on an instrument only — and in that case by NOT singing and NOT emoting so much, there is considerable mental space available to pay attention to finger placement and precision, as well as recollection, which simplifies everything greatly. What is difficult is keeping the chords in mind while I’m busy creating an emotional connection. To go back to the right/left brain analogy, I need to get the left brain to add keeping track of the damn chords (not just the lyrics) and fingering precision while the right brain is keeping track of the emotional part and holistic aspects. It’s a precise mental dance.
The process is very similar to language acquisition. I remember when I was in Argentina — I could speak Spanish when I arrived, but could understand no one. In about 5 weeks I deemed myself “fluent” — I could understand the people around me. However, I found in the next year that often I moved my hand as I spoke — as if I were illustrating with my hand the process of taking the direct/indirect object and jumping it ahead of the verb before speaking the verb. I also went through several months where I often stuttered a bit when I spoke Spanish — caused by anxiety, which reinforced the anxiety, ugh. I was there for 16 months. By the last 6 months, all of that had subsided — I thought in Spanish, and my brain would correctly place the direct/indirect object in front of the verb without having to throw it forward (overthinking,) and the stuttering no longer happened.
Right now, in order to get all of the chords correct while performing I have to “overthink” and the fingering mis-steps and chord misses are analogous to the “stuttering” I went through in Argentina (which happened when I was speaking in “important” situations — not, for example, when I was simply speaking to peers.) (Well…when the fingering mis-steps aren’t simply due to lack of skill…that also happens.) *sigh* The only way forward is through.