My son is now a shade over two years old and continues to call me Hi, There!
As far as he’s concerned, this is my only name, that’s his story, and he’s sticking to it. Even if we painstakingly recite ‘Mama… Papa… ‘ with pointing, he’ll happily repeat back, ‘Mama… Hi, There!’ Now that he’s started saying a lot more, there are combinations like ‘Buh-bye, Hi There!’ Even during moments of relative anguish, he’ll wail ‘Hiyyyyyyyy, Theeerrrrre‘ beseechingly from another room.
This has been going on long enough now that I’m forced to confront the possibility that maybe he’ll never grow out of it. I try to imagine a disaffected teenager walking into the room to ask, ‘Hey, Hi There, can I borrow the car tonight?’ or whatever.