When Tony Stark is twelve he uses his own DNA with a little bit of DNA from his Ditto, Mycroft, to create a clone of himself. As Tony's parents are missing and Tony is still a child, Sherlock is raised by Jarvis. His upbringing results in an Unova accent matching Jarvis'. However, because of his Ditto DNA, he can imitate the voice of anyone he has heard speak, and even understand Pokémon.