I took a semester of phonetics ages ago to improve my Spanish. I really got into it and enjoyed it. It made me sound like a pro. I thought it was a load of fun.
I began to think that I could use similar techniques to purge the southern accent from my English. That worked, too. I could talk flat general-American English just like some newscasters.
Then, after I stopped worrying about it for a while, the southern accent came back with tremendous intensity, greater than before.
I should have just left it alone. 😆
Fuenteovejuna did it 