Blossoming
Practically my first day at Grammar school I had my speech corrected by a teacher in front of the entire class. It was one word and definitely a widely used local pronunciation. I just wanted to curl up and die. I had to remain standing at the front of the class while she gave a mini lecture on how ‘common’ people spoke. Common people like me, as Jarvis Cocker famously said.
I remember my first days at Infants' school in SW London when I suddenly realised that my northern accent was an oddity. Other children laughed at me for saying grass in a way that rhymes with mass, and so on. There are still the occasional words that are northern, in spite of there being about 68 years since I left Accrington.
We had a very snobbish French teacher at my grammar school who declared that there was 'no excuse' for regional accents. I loathed her.