I know, I know - it sounds deluded. I mean, he's not even 4 months old yet. But I swear he did it!
I was playing with him in his bassinet, and I looked at him and said "I love you". He looked back at me and, clear as anything, said "I [gurgle noise] goo"!
Now granted, that could have been "I love you", or it could have been "I just pooed"; I can't be certain. But I am going with "I love you". So I think he's at least imitating sounds he hears.
What a sweet and dear little boy!
Here is a pretty current photo of him. He loves kicking and playing in his bassinet, and he frequently kicks off most of his swaddling blanket and wears what's left like a sash. How cute is this?