Although I typically dislike country music, I listen to a lot of Patsy Cline because she has the clearest female voice that I have ever heard. In her most popular songs, her southern accent is barely noticeable. In her least popular songs, her southern accent is thick. I suspect that to reduce her accent, she carefully enunciated her words with outstanding control of her voice. You have to listen very carefully to fully appreciate the details in her voice. It's hard to believe that she died 8 months before John F. Kennedy died.
https://www.youtube.com/watch?v=hTDSprGJOTc