Given that was the very first filmed episode (as a second pilot) it can be forgiven (The Man Trap was the first aired). I can’t find a reason for picking “T” later on in the series, but it sounds better than “R” when announcing his full name to an alien ship. “Tiberius” didn’t even come along until a later animated episode, and still wasn’t canon except to fans until it was used in The Undiscovered Country.
“James R. Kirk” lol
Gotta love the episodes before they nailed everything down.
They called Starfleet like four different things before they settled on Starfleet.
Given that was the very first filmed episode (as a second pilot) it can be forgiven (The Man Trap was the first aired). I can’t find a reason for picking “T” later on in the series, but it sounds better than “R” when announcing his full name to an alien ship. “Tiberius” didn’t even come along until a later animated episode, and still wasn’t canon except to fans until it was used in The Undiscovered Country.