While my parents were here, Naomi learned to say Grandma and Grandpa. Applying the correct title to the correct person was a little harder, though. She basically used the terms interchangeably. I think my parents were amused by this.
At the grocery store today, Naomi spotted someone who looks like my mom (or at least has the same color hair and hairstyle). Naomi immediately commenced pointing and yelling "GRANDPA! GRANDPA!" I'm hoping the lady didn't notice!