Always pronounced it "puh kahn" - only yokels and exaggerated doofuses have ever called it "pee can". My inbred cousins up in Oklahoma would say pee-can, but literally, they're all either half retards, or full retards. Its the part of the family tree we don't discuss, because we're pretty sure some of the branches circled back to the root.
I'm...actually not a fan of the pie. I like to shell and eat the pecans by themselves. Straight off the tree (or the ground underneath it) if possible.
One is an edible nut -grows in an orchard. The other is a half-gallon milk carton carried in the covered bed of the pickup when our boys were young & it was ok to drive with little kids in the pickup bed.