Growing up, I called my grandmother Grandma.
We were Jewish, but also American. There was never any question but that my grandma would be Grandma. Even if she was born in the Old Country and, like all my friends and all their grandparents, spoke with a Yiddish accent. I used to think, in fact, that in order to be a grandparent you had to have been born in the Old Country and speak with a Yiddish accent.