ER words

ER (now 17 months) has a few words and between them and his gestures we can often figure out what he is trying to tell us.  My younger sister, her husband and their almost 9 month old visited this past weekend.  We were tying to teach ER their names.  In the end he concluded that my sister was Ima (which she calls herself) or Mommy, their son was baby or Dani and my brother-in-law was "Zayde"?!