Well there's not much to it - so far (at 15 months):
ma-ma (even after my request to him to say "da-da")
woowoov (woof, i.e. from a dog)
Loves Veronica, the neighborhood dog, as did Avery and Connor. Everytime we go out to the front yard, Bennett immediately points towards Kevin and Julia's house, and says woowoov -- heading over there to see the dog.