I grew up in D.C. I went to college in W. Va., where I first heard “used to could...”
There are a lot of Southernisms that have spread throughout the country:
“If I would have...”
has displaced
“If I had...” or
“Had I...”
“If Trixie hadn’t barked, we’d all be dead...”
has become
“If Trixie didn’t bark, we’d all be dead...”
I would say that, in news items, on the radio, etc., “ten-year anniversary” has COMPLETELY displaced “tenth anniversary.”
This isn’t a matter of grammar, but when David Knight fills in for Alex Jones, I can’t listen. He says pent-cil, healt-th, wealt-th, etc.
Pet peeve of the day: "my [wife/husband/shackup] of two years." A marriage can be of two years because you were married in 2013, but a wife of two years is much too young to be getting married. I wonder what Elizabeth Warren would say...