My first grandaughter went thru a series of names as she learned to talk. I liked grammy but her mother called me grandma so that's how it stayed until my 4th grandaughter and when she was about 18 months old, she named me gaga (with a soft a) and it has stuck. Some of the older ones even call me gaga now. When she was about 4 years old, she looked at me one day and said "gaga, you really are grandmother aren't you?"