This reminds me of a true story I recall from my youth. My family had moved from New York to Rhode Island where the accents can be quite different. A few years later another family moved up when my dad hired the father. Their daughter was in 2nd grade or so and was reading aloud to the class. A character in the story was named Carla. Coming from NY, we pronounce all the letters in that name, as most speakers of English anywhere do. There are certain accents in Rhode Island and nearby Massachusetts, that do not pronounce the R, which are derided like a cockney accent might be in London. The teacher, who should clearly have known better regardless of how the teacher grew up speaking, repeatedly told the child she was saying the name incorrectly.