['My nephew just said his first words last week.', 'How exciting!  I remember when my girls said their first words!  What was his first word do you know?', 'He was saying da da, so we count that as dad. I love that little guy.']
Yeah, that seems to be what a lot of little ones say for their first word.  Something about it being easier than ma ma - congrats to the little tyke!
My nephew just said his first words last week.