Ferrara, I agree with your opinion that the words should be "my ma chere amie-o" and not "my m'cherie mi-o" as it appears in DigiTrad. I don't know how Hank Williams intended to write it, but "ma chere amie" is at least good French - although I too am in doubt whether it should be "chere" or "chère." I'm pretty sure the masculine form is "cher" though.

I too have seen menus that offer "roast beef with au jus". Redundancy is a common feature of language. Have you memorized your PIN number? [Personal Identification Number number].