Yes. Guitar players after a certain point learn to improvise spontaneously, like playing over a backing track. Or when famous musicians improvise on their existing solos and change the notes during live performances. Funny thing is sometimes when I play guitar, I also reach points where I feel lost or stuck and don't what to play next. I call that stuttering on the guitar lol. I'm also not sure why singing doesn't involve singing. But I read somewhere that singing and speaking come from different parts of the brain.......that's just what I read. Dunno for sure.