I just remembered: I have one friend who calls me Jimmer. I can't remember how that got started. I don't mind it; in fact I had forgotten about it.

I tend to think of nicknames ending with –er as a British thing, but maybe that's only because Jimmer occurs in one version of WHAT A MOUTH by R. P. Weston. I can't recall hearing it anywhere else.

My friend, by the way, is American, but I know she has visited England.

Attaching –s, as in changing William to Wills, is another thing done in the UK but not in the US.