I daresay it was a book sold in America for ‘English Pronunciation’, or something, but it definitely spells out an American accent, which is understandable. Not sure why the person in the post feels so called out by it, other than ignorance of one’s own accent, but whatever, the ‘translations’ are pretty fun.

I always kind of enjoy reading spelled out accents as a literary exercise. Pratchett was great at it with the Mac Nac Feegle, for e.g., and wasn’t that James Joyce’s whole thing?