Many years ago I had fun memorizing a couple hundred digits of pi. I used 5-digit groups for the first hundred, but after that I found it was better to use variable-length groups -- easier to make up a story around them, harder to mix up the order, and so on.  What's weird if I memorized them in my native language, which is not English, and it's really hard for me to recite the decimals in English. I have to pronounce them in my native language and translate the digits into English on the fly, which is hard to do at the same time. I memorized the sounds of the numbers, not the numbers themselves. I never decided to do that, it's just how I naturally did it. I wonder if other people memorized the shapes instead, and would have an easier time saying them in a different language by just visualizing the numbers instead of having to pronounce them internally.  I'm not a musician but I'm curious as to how you learn a song. Probably you 
 don't ju
 st recall the specific notes or chords, but some higher-order pattern? Is this something you can explain in simple words?
as long as i've heard a song more than 10 or 20 times, over the course of a few days, i automatically learn it and could not unlearn it. but the tricky part is if i have to learn (memorize) a song on short notice. for that, i absolutely just make a chart and then read it. i am pretty much bullet proof that way, in that case i would only have to hear a song once, i just write it down the first time. but in the rare case the director may say 'absolutely no reading' .... well ........ i'd be fucked. until the age of A.R. glasses