The Boy actually said "Bye-bye" today, to Aunt L & Uncle B, who came by to visit and play Buzz TV, a quiz-show game for the Playstation 3. We were saying goodbye to them, and we heard a high-pitched voice say (with a wave), "Bye-bye!"
It was very exciting.
Granted, just like his "I love you," it'll probably be two months before we hear it again. But, still.