What the "ba" does that mean?

Brett uses "ba" or "ba-ba" to mean a whole bunch of things:
Baba (my mom), grandma (Randy's mom), Barney, puzzle, pasta, pillow, biscuit, bar (granola bar — he's too little to drink in bars). The variations in pronunciation are subtle, but if you listen carefully, they're there. The boy's going to be a language genius.