What's in a Word

Here is a list of words we think Madeline attempts to say:

da-da
baby
bye-bye
doggie/duckie
thank you

We are biased in that we speak the "Madelinese" language and the words are spoken in context.

Which leads me to...why is "mama" so late on the list of words babies say!? Thanks for the payback for all the blood, sweat, and tears (literally)!