LOL about “shudder, Mana Last name.”
The toddler of our next door neighbor called my wife “grandma” not long ago. This was the first word he uttered to my wife (he’s just learning to talk.)
(Of course, my wife did not understand that word which was spoken in Indian. She asked his mother what it means. I think it is out of the respect. I later checked it with our Indian coworker, and was told that the kid uses the same word to address his grandma and anyone who is about his grandma’s age. Interesting. I am aware that in some culture, the kids are expected to use Uncle/Aunt to address all adults their parents introduced to them. Grandma/grandpa things are new to me!)
Re: Mama last name.
I think this is a common practice for the people from the mainland of China. (At least I think so.) This is out of respect as well as implying “we are close, not strangers” I think. Not sure whether it is the same in several other parts of Asia like the east or south easy Asia: Japan, Korea, Taiwan, etc. However, the “seniority (age, rank)” thing, as I heard, is a part of Japanese and Korean languages. I heard that is why they often ask each other’s age when they first meet with each other; otherwise they do not know how to address the other person and they even have a great difficulty to hold on a conversation (as “honorific” is an inherent part of their everyday language.)