Just like in Only Fools and Horses where Trigger is the only one who calls Rodney; Dave, Vegeta has a weird quirk where he calls Goku; Kakarot. In Only Fools and Horses, Trigger is known as the nice but dim type, but you certainly can’t accuse Vegeta of being an idiot.
So why does Vegeta call Goku Kakarot, when the rest of the common tongue-speaking world call him Goku.
Vegeta calls Goku Kakarot because that is Goku’s Saiyan name given to him at birth. Vegeta considers it his proper name and so insists on calling him Kakarot even though everyone else is happy to call him Goku.
It’s not just Vegeta who does this.
The first time we hear of this mysterious name Kakarot is when we first meet his brother Raditz at the start of Dragon Ball Z.
Later when we meet Nappa he calls him Kakarot as well. So it’s clearly only the Saiyans who care about his magnificent Saiyan birth name and don’t want to use his puny earth name.
Oh, and of course the people who named him, Bardock and Gine, would probably keep calling him Kakarot if they didn’t tragically perish when their planet accidentally exploded….right Frieza?
A Saiyans pride…
Sure Goku and Vegeta got off on the wrong foot, with Vegeta trying to destroy his planet along with everyone he ever loved.
But after Goku made Krillin spare his life things have been going great between the two of them. So why doesn’t Vegeta respect Goku’s wishes and call him by his earth name?
Vegeta has too much Saiyan pride, that’s why!
Goku is a dirty human name, while Kakarot is a proud Saiyan name, of course, the prince of Vegeta is going to use it.
Vegeta probably sees it as his slave name and is perhaps always low key insulted when anyone else uses the word Goku.
Name’s can be hard to unlearn, they make up a vital part of a person’s identify. Cat Stevens became Yusuf Islam in 1978 but will forever be known as Cat. On the other hand, Cassius Clay’s name change was a lot more successful and will forever be known as Muhammad Ali. For me, and millions, he will always be Goku, but for some, he’ll forever be Kakarot.