Here’s something that has perplexed me for some time. Instead of looking it up I figured it’s better to ask here.
How do some names aquire their particular nicknames when the nicknames have nothing to do with the name?
Examples:
Dwight = Ike
Margaret = Peggy
John = Jack (At least they both start with “J” and have four letters.)
Margaret-meg-peg-leg, just kidding about the last.
Eisenhower=Ike
I’ve heard of this one.
Jon, Juan, Jacques, John
Jacques is the misfit in this; it’s english equivallent is James, not John.
Agreed, but it is still the source of the “jack” nickname, I believe, or a spelling very similar to Jacques or Jaques. After all wasn’t English invent by the French? 
No it’s not, actually. When I was researching my name (before it was my name!) I read up on the origins of “Jack,” and that it is related to the French name “Jacques” is a myth. I used to have a good nomenology page in my favorites but I’m at work now and can’t find it, so here’s the Wikipedia page, which basically says the same thing: http://en.wikipedia.org/wiki/Jack_(name)
However, in French-speaking company, I am always Jacques. I’ve come to the conclusion that it’s impossible for a French person to say “Jack,” so I just go with it.
P.S. The equivalent you’d need would be “Jean,” not “Jacques.”
(I think of Jean Calvin/John Calvin…)
Surnames too, at least here in the UK. “Dusty” Miller (that one’s fairly self-explanatory), “Nobby” Clark - why?
Richard=Dick as in Richard Bruce “Dick” Cheney
Or in Richard Hedde, Richard Waud, Richard Lesse, etc.
djm
Largely Cockney rhyming slang is my understanding.
poor Nixon…so soon forgotten
why I can remember when he was the favorite Dick
In Hindi, “Nabi” means “Clerk”. Hence, anybody called Clark in the British Army in India would be called “Nabi” or “Nobby”. The slang made its way back but the meaning didn’t.
According to Chambers 20th Century Dictionary, an obsolete form of the name “John” is “Jankin”, which apparently mutated into “Jack” and “Jock”.
I thought it was from nobs like me?
Please refer back to “Richard Hedde” as listed previously.
djm
Really James is an odd translation from the same name as Jacob. Thus Jacques makes sense, and Iago (consider that J and I are the same original letter in Latin–which makes the Dutch use of J make more sense), from it add Santo and we get the Spanish Santiago.
If you think those are odd, consider the gaelic versions Seamus and Hamish.