Austin loves to sing his "BCs" (what he calls the alphabet). He's very good now, but when this video was shot, he was just getting the hang of it. At the time, he could actually say the alphabet completely, but just not fast enough to keep up with the song on his toy. That's why he's only singing every few letters. Plus he gets distracted by his awesome dancing!
I apologize for the length. I just like watching my kid. Plus I couldn't get a shorter version to load.