[scrozier]

The distinction between reading music and sight reading aside (others have addressed it), learning to read music is honestly just rote practice. In the grand scheme of things, it's really not that hard. To play simple songs (all within one octave, say) from music on a staff on an instrument, you really only have to learn twelve associations of positions on the staff to a key on the keyboard or a fingering or an embouchure and a fingering, etc. It's far easier than learning a language or a programming language or the rules of hockey. From there, it's just extending those associations higher and lower, and learning other aspects of music notation, like note durations. It's just standard repetitive learning. No magic or particular talent is involved.