After months of maternal ambiguity, she certainly knows that word now, and walks around constantly saying it in different ways.

Mommy–declarative (there’s my mommy)
Mommy–imperative (be my mommy!)
Mommy–possessive (be MY mommy!)
Mommy–interrogative (where’s my mommy?)
Mommy–interjection (mommy is a force of nature!)

Mommy–so much more than a proper name