Instead, when not in their view, they were called "Oma" for grandmother and "Opa" for grandfather. If we spoke to them directly, it was always "Omi" and "Opi", the "i" pronounced as "ee". Example, "Omi, the blanket you're knitting is beautiful," or "Opi, thanks for showing me how to gut a fish." (All things my grandparents did.)
I thought that maybe these were just nicknames, but the different spellings made me wonder, whether direct or indirect. Thank you!