When I was little my sister (she is 6 years younger than me) use to call me Nelope (short for Penelope but she couldn't say it) and my name is Kaci! No idea where she came up with that. She was about 3 when she started it!
She also referred to herself as mom and she called my mom Brittany (her name). Then my brother was neighbor boy. And she always said we got my Dad from Albertsons (grocery store). She was the baby so we amused her and let her do it lol