When can my baby hear me talk or listen to the music I'm listening to?
I don't think anyone really knows. But it's probably around midpregnancy. You have to remember, there are two aspects to hearing:
1. There's the mechanical aspect, wherein the ear drum moves back and forth, sending impulses down the acoustic nerve (Cranial Nerve VIII) or through direct vibratory transmission through the skull bones, etc., to the auditory part of the brain. And...
2. The auditory processing of what comes into the brain.
Any answer you get on this will be speculation. I myself speculate that the auditory processing doesn't fully mature until after birth, but there's a certain awareness that circles around these areas of the brain to help establish the processing. So sound stimuli can only help promote an orderly maturation, even in the fetal stages. So talk, read, play music, etc.