Nicknames are not necessarily childish. Shakespeare has lots. From King Henry IV (both his parts) we have Hal for Henry. Then there is somewhere, I forget where, Noddy for Edward.
Besides Shakespeare, Edward is also parent of Ed, Ned, Ted (also short for Theodore), and some of these have their own versions, like Eddie, Neddie, etc.
Charles has Charlie, Chuck, Chaz. Robert (I should know as in my family the first male for 4 generations now has that name and they have to have a different appellation to avoid confusion) reduces to Bob, Bobby, Rob, Robbie, occasionally Robin but that's really a different name.
Baltimore is famous for short nicknames. The ideal is a name of one syllable. My father-in-law, Elmer, was known as 'El' or 'Elm', for instance. My wife's godmother, named Ada (can't get much shorter than that) was called 'Ades' (this was before AIDS). Wierdly, if you have a one-syllable name, it gets longer as a nickname, as Ruth and Joyce become Ruthie and Joycie.
