[Brybry]

For day-to-day familiar conversation we generally use nicknames for grandparents in the US and that's what is in our contact list.

There are probably hundreds or thousands of nickname words for grandma based on a variety of cultural backgrounds, family tradition, and mispronunciations by grandchildren.

The language we use really depends on setting. In a more formal setting we might say paternal grandmother/grandparent. Speaking to a friend we might use the nickname, or we might say the ambiguous 'grandma' or we might say 'grandmother on my dad's side' or 'dad's mom'.

It really depends on the situation and familiarity and formality.