Regardless, as I said, they’re separate names with different origins. Anyway, I don’t think I ever met a Jonathan who went by John (certainly not with an H). Perhaps it’s a regional thing.
You and me both.
Otternell–AFAIK, the only people who still go by Dick are the ones who have been doing so for approximately 70 years already.
As for why Dick is a nickname for Richard: I know we have had threads on this phenonmenon before, but I failed on search. I don’t remember exactly why it was done, but it was part of a whole trend for nicknames that rhymed with a shortened version of the full name.
Richard–Rick–Dick
Robert–Rob–Bob
William–Will–Bill
Margaret–Meg–Peg
Edward–Ed–Ted
And so forth. And these changed-letter nicknames are hardly used anymore, even if the full names are still used.
Come to think of it, all the changed-letter versions have kind of a jaunty feel to them. Maybe jauntiness went the way of the fedora.
Anecdote time: An old coworker of mine had a kid who’s name was Cooper. Since this was before the last-name-as-first-name thing was so common (the kid would have been named around 1990), I inquired as to the origin of the name.
Seems that his name was really Richard Cooper Lastname III. Grandpa, aka Richard I, went by Dick. Dad, aka Richard Jr., went by Rick but didn’t care if people called him Rich. That left the problem of what to call the new baby so as to minimize confusion. So mom and dad chose to call him by his middle name, Cooper.
Everybody was happy, except Mrs. Richard I. Who simply could not understand why they didn’t just call the kid “Dickie.” Dickie being such a nice name and all. And in fact insisted on calling him Dickie for a while until Richard I (aka Dick) told her to knock it the hell off–that nobody wanted to be called any form of “Dick” in this day and age.
Dickie. Heh.
Me neither. I’ve met Jonathans who go by Jon who don’t bother to correct people more than once if they spell “Jon” with an “h” however, as they have found that trying to convince people that they are not the same name is like talking to a brick wall.
Oh, and I knew a guy who’s given first name was just “Jon.” Poor guy. Everybody
Bingo! It’s a Gay male thing.
In the old days also Hob, Nob, and Robin
I’ve never heard this stereotype, and I’m surprised to now. I only know two gay men who don’t go by nicknames - for one there is no common nickname for his name, and the other is a Jonathan. Well, I’m fairly certain that Jamie, Tommy, Stan, and Zack are all nicknames, but I have a by-marriage uncle whose legal name is Don so you never know.
Are Bear and Slave shortened first names or not ?
I have known several “Johns” which were shortened from “Johnathon” and one “Jon” which was his whole given name, and a “Jon”, and a couple “Johns” which were used by men christened “Jonathon”. So there are at least those cases:)
John is not a diminuative of Jonathan.
I gotta ask given all this John/Jon stuff.
AFAIK they are pronounced the same way. Or at the very least, with my limited speech skills, I can’t pronounce them differently.
I can just imagine an Abbot/Costello hello Jon/no its prononced John skit here.
Starring Stewie Griffin.
Cecil covered why Dick is short for Richard.
Balt, Lazar (as in Lazar Wolfe from Fiddler on the Roof), or you could always do something like Bart, which, even though the “r” isn’t placed in that order in the original name, a nickname doesn’t have to come strictly from the given name (There’s only one B in Robert… so Bob would be out of luck if that were the rule.)
And Brian … you need two to pull that off… and we all know Brian is Stewie’s other half when it comes to comedy!
One would think. But then I met someone who spent 10 minutes complaining because I pronounced Dawn like I pronounced Don and that was wrong . . .
You shoulda told her if she shaved a bit more often you’d probably do better
oh, that’s bad. but funny. 
My name is Cynthia, but I go by Cyndi. My best girl friend is Rebecca but I still call her Becky. Recently I realized everyone else calls her Rebecca now and she told me she thinks of Becky as a kid’s name.
I will be Cyndi until the day I die.