This is a tough one. It's either:
"Woof-foof", which is how he greeted Lillie Biscuit and her sister, who were playing in the back yard when we got home this afternoon, or...
"Mama! Mama! MahMAHHHH!!!"
Which was his reaction when his daddy came on television at 6:20.
*EDITED TO ADD*
The reaction was pure excitement and joy. He was waving and calling out to his daddy (although he was a little confused as to what to call daddy), not screaming for me...