Reading music is the ability to look at a line of music and being able to hear it in your head, or at the very least play it back almost immediately on the inst

Reading music is the ability to look at a line of music and being able to hear it in your head, or at the very least play it back almost immediately on the instrument of your choice. My buddy's music "reading" ability is more on the order of a kid who doesn't really read but knows a few words. He's effectively illiterate, but he's not stupid and can figure it out with difficulty.