St. Patrick’s Day is coming up, so now is a good time to mention that the diminutive used in Ireland is Paddy, Not Patty. Here’s why:
Paddy is derived from the Irish, Pádraig, hence those mysterious, emerald double-Ds.
Patty is the diminutive of Patricia, or a burger, and just not something you call a fella.
There’s not a sinner in Ireland that would call a Patrick, “Patty”. It’s insulting. It’s really as simple as that.
And there you have it. Paddy, not Patty.
(h/t Grammar Girl.)