Shoot, I was hoping you'd say I was worrying for nothing.

CCN, I'm hoping that since your DS took a similar path that it will prove to be nothing. I might give it a few more weeks or so to see if it improves or disappears.
DS-3 was definitely in an observation phase for a long time. We could tell he was absorbing things, almost like he was taking everything in and processing it so much that he had no time to talk. He actually knew his letters shortly before 2 (would pick it out from a pile or on his computer programs), but couldn't verbalize them until way later. DH thinks he's just thrilled to be able to repeat us, so we'll see.
Thanks everyone!