All my grandparents have passed a while ago, and honestly if I could, the one thing I miss most is talking to them. Even when they didn't understand me. I got frustrated too but now that I'm older I realize I was just scared of losing them. Their nodding along was their way of making sure I didn't worry about them. They didn't want me to worry about them, as impossible as that is. I don't know what type of relationship you reading this have with your grandparents, but if it's not completely toxic go and talk to them. Even if they don't understand. They're used to you babbling in their face, you did it your first few years anyway.