i hope i'm not tone deaf, or my endeavor to play slide is a lost cause as well :)
definetely don't have perfect pitch, but my relative is okay. but i'm sure it could develop further. but hearing differences in pitch on the guitar is different than hearing yourself trying to sing notes.
someone could have good skills with it on an instrument, but not be able to sing well, or even match tones well with their voice. it's a whole different instrument.
i can't afford a coach, so i have to get what little info i can, wherever i can find it. i did make some pretty dramatic progress from my starting point, which is good, because it shows that it can be worked on. but i hit a wall, and don't know where to go from there to get where i want to be. don't get me wrong, dramatic progress is from horrible to bearable, or maybe even pleasant on some songs.