Little willy

I had live in the US for mauve a couple of years and I had to ask who was william "x" at work while i was working on some milking list and a co worker says that's Bill "x" And laughs. And I asked of it was a typo. She was so confused that i was asking that and I was even more confused trying to figure out why was Bill short for William. Seriously why not Will????

I think because Will is short for Wilfred