Now we mix it up and I alternate "Elmer" and "Arthur" for whose tune it is- at Elmer's insistence.
A few weeks ago, he asked for "Arthur's Tune" and proceeded to sing along with me. He sang almost all the words correctly (and some of them are doozies for a 2 year old!). I was so surprised, and he was so cute, that I giggled my way through the song. He giggled too, and I can't really fault him for being out of tune. He's obviously learning the song just fine!
I think my proud mama heart just grew a few sizes larger - what a sweet experience singing this song together!