(Or, why I incorrectly called both sets of grandparents Yen Yen and Yeh Yeh when I visited them.)
In most families, there are specific names for each grandparent, whether you include the surnames (or first names) or have diminutives or nicknames or use terms from the language of their heritage. Grandma, Grandpa, Grandmother, Grandfather, Gram, Gramps, Mimi, Nana, Papa, etc. In one family I know, the 5-year-old called his mom's dad "Bob", and once made the awkward Grandparents' Day introduction of "This is Bob. He lives with my Grandma."
But Chinese is the only language I know where it matters whether the relationship is from the mother's side or father's side, or for the uncles and aunts, how old they were in relation to your parents.
This is the cleanest explanation I've ever seen. But hold onto your hat, because The Complicated Chinese Family Tree is still a wild ride.
Now, as to how that played out in my family:
Let me first make it clear that both my parents' first language was Chinese, but it was Toisanese, which is a village dialect of Cantonese. (Nowadays, if you say "Chinese" without specification, that means Mandarin.) And whereas they grew up in a Chinese church with bilingual worship services, the church I grew up in was wonderful but definitely all in English. So my Chinese, whether Mandarin-Cantonese-Toisanese, hovers right around zero. Some people speak "Dora Spanish"; I speak somewhat less than "Kai-Lan Chinese".
My Por Por and Gung Gung, my mom's parents, lived in CA; my Yen Yen and Yeh Yeh, dad's parents, lived in MI.
And when I was at home in MD talking to my parents about their parents, I kept them straight. And because of the vagaries of English, I sometimes asked my friends which side of the family they meant when they talked about their grandparents.
And when we visited MI and my dad's parents, Yen Yen and Yeh Yeh, the family in the area was my uncles and their families. All paternal.
But then when we visited CA and my mom's side of the family, I was a linguistic wreck.
Both my mom and dad have brothers and sisters. But on mom's side of the family, she's the only daughter with kids. So to me, her parents are my maternal grandparents, Por Por and Gung Gung. But to every other cousin (all ten of them!), that same couple is their paternal grandparents: Yen Yen and Yeh Yeh. And I knew that intellectually, even when I was little. But could I get my brain and my tongue wrapped around it at the same time? Not so much.
I guess the takeaway is that I'll just call it a blessing that the only names we used in Chinese (Toisanese) were the grands, because I have a LOT of aunties and uncles, in different ages relative to my dad's age. (Yes, you read that right: not my parents, my dad. When my mom married my dad, the relationships got enumerated in relationship to him regardless to her previous geneologic relationships. It's one repercussion of a culture in which you truly marry out.)
Short version: English makes us soft. In fact, my dad's sister says that when she was tiny her mom drew a hard line on calling people by their correct title, but by the time the youngest of the sibs was talking, it was much more informal and everyone was just "auntie" and "uncle", not "third uncle on my father's side" and the like. Similarly, my mom told me once that her dad drew a hard line that for her and her sibs to keep in practice "only Chinese will be spoken in this house!" Then silence reigned supreme for weeks.
Do I wish I'd learned Chinese? Honestly, yes, I wish I'd learned Mandarin. In this day and age that may be the most useful. But so far I haven't learned any more Chinese than Firefly has taught me. And that's a lot less than Nathan Fillion knows.
Nathan Fillion references Firefly on Castle