Earl
James Potter called him Earl as soon as he learned that he called him "Jasp" in front of his grandparents.
The little boy, his godbrother, didn't care for the reasoning, that both of them had known the first James and still always thought of him, too, when he said "James", and so, after a little thinking about how he had become "Jasp", Teddy became Earl.
It didn't bother him.
It was like a private joke just between him and James that nobody else understood or used.
"How are you today, Jasp?"
"I feel marvellous, Earl, just marvellous, thank you for asking!"