Supercalifragilisticexpialidocious

Another word request, though I thought its origin fairly obvious. Turns out, is isn't as straightforward as all that. Supercalifragilisticexpialidocious is a 34-letter word many may know from the 1964 Disney film Mary Poppins. It apparently is a nonsensical word supposed to describe feelings of extreme happiness or glee, and most people think the story stops there. However, Supercalifragilisticexpialidocious has been around much longer than the movie, and actually is a modification on the title of a 1940s song titled Supercalafajalistickespialadojus. This has some etymological sense, but not much. For example, the superlative super clearly adds a cheerful, happy ring to the word (dating back from PIE uper "over" through Latin). The word espial means "watching someone without being seen" but that's definitely not a root (though it invokes thought of the word special, which would make sense in the word). Most likely everything except for super is gibberish, despite some myths you can find online.