Almost five months old and changing every day. The latest development is the production of deep, throaty growls. She mostly rumbles them out when I have her on the change table. That's kind of when I'd hope she'd develop the ability to say,
"Awfully sorry about that one, Mum. It sure is a doozy. I'm terribly thankful for your tireless patience in this tedious process."
Maybe when she starts talking.