@Background Pony
The parents have long been called Clyde and Sue by the fandom. (And if you’re confused about Sue, check out the names of the ghost monsters in Ms. Pac-Man.)
@richiebenaud
Go away, everyone knows about Pac-Man.
Now, on the subject of the names, I have a completely made-up theory that might help. After Pinkie got her cutie mark, her siblings liked this new thing called “fun” and asked if they could have nicknames too. Pinkie, being Pinkie, decided it’d be even better if the names rhymed, so they chose Inkie and Blinkie. They tried calling their parents by new names too, but those two insisted on being called something sensible, so they got Clyde and Sue instead of rhyming with the others.
@lackey_h
Actually, the blind-bags call her “Trixie Lulamoon”. It does seem kinda human, but as you said, she does pronounce it “Tricksy”. “Tricksy Moonlight” changes her name into “Trixie Lulamoon” when she enters High School.
@Rainbow Dude
For all we know, Carrot Cake is the kid of Gilded Matrimony and Honey Swish, and Cup Cake is the kid of Bluebelle Glam and Lipgloss Discus.
I don’t know why people are complaining. The show has given our fanons a shout out many times. And all we do is complain when sometimes fanon dosen’t turn out to be canon.
@Takuto_Shindou
To me Time Turner is the equivalent of John Smith. The Doctor pops up on Equestria with an hourglass a cutie mark, and John Smith would be a weird name for a pony.
@Rainbow Dude
Twilight Velvet and Twilight Sparkle provide a new interesting concept - the idea of some parents passing name elements, that are not in the form of a surname, down to their children.
I’ve mentioned the Apple family before as one which has no definitive naming links (outside of a general theme).
And Diamond Tiara… now she (and Silver Spoon) bring up a whole other interesting point: Their names match their cutie marks way too much to be coincidence (they’re not the only ones either). This brings up the possibility that ponies can change their names when they get their cutie marks… which adds a whole new level of ‘oh god what’ to pony naming convention and could go some way to explaining why many related ponies have completely unrelated names.
As if this isn’t all bad enough - it hit me earlier that Trixie is an oddly normal (normal to us i mean) name for a pony to have and now my head is wondering if she’s the kind of pony who could have been called ‘Tricksy’ and decided that spelling wasn’t exotic enough for somepony as Great and Powerful as she was.
@lackey_h
Twilight Sparkle and Shining Armor are siblings, and Twilight Velvet is their mother.
Applejack, Big McIntosh and Apple Bloom are siblings.
Filthy Rich is the father of Diamond Tiara.
There are no surnames, only Theme Naming at best.
@Rainbow Dude
Except the cake family rather ruins your claim as everyone in their family is ‘something Cake’. Which implies that the latter part of a pony’s name can be used as a surname in some families.
Pony naming is, frankly, a mess and a half at best.
@lackey_h
Since ponies don’t have surnames, my theory is that they just named their daughters after Granny Pie.
(And also named Pinkie after Nana Pinkie, because she’s pink.)