Well Joe, the reasons I don't hold with memorization through understanding are two: I don't understand chords; and I once misspent some time memorizing lyrics. It's pretty quick for me to memorize lyrics to the point where I can write them down again without mistakes. Getting that far might help a LITTLE in performing songs, especially for the first lines of stanzas but for the rest of the song, for ME, I've got to know the lyrics WITHOUT any reasoning or mental tricks to be able to sing them well. This means practice, practice, practice. I think too, that chord changes are a harder to learn on the autoharp. On the guitar, your fingers can learn how to jump from G to C to D chords, and if you want to do a song in G# or A you just capo 1 or capo 2 and your fingers still know where to go. On autoharp, I think your fingers would have three completely different things to know the keys of G, G#, and A. But at least the actual fingering of the chords is easier :)

Yes, there are common patterns in music. Whenever I don't think I'll be bothering anyone, I try to sing along every song, including the ones I've never heard before. It amazes me how often I can guess the words, let alone the notes. I think if you can guess the melodies to songs, sooner or later you will be able to guess at chords that would fit. They may not be the "right" chords though. Remember that even for a beatles song there are usually the arrangements they played, the simpler arrangements that got published, the easy guitar chords version, and the beginners guitar chord version, and several souped up jazz chord versions that are harder than anything the beatles ever recorded.