I called my maternal grandparents Grandma and Grandpa.
I called my paternal grandparents Nanny and Papa.
DH and I are called Grandma and Didi. Didi is short for Grandpa in Ukrainian. However, our DD gave us the choice of what we wanted to be called. From what I hear the grandchildren may put their own spin on our names...so we'll have to wait and see what we end up being called. DGS is only 6 months old.