https://www.metv.com/stories/frances-bavier-thought-that-andy-griffith-made-up-the-mayberry-diction-on-the-andy-griffith-show

"I thought Andy was making it up."

https://www.metv.com/stories/frances-bavier-thought-that-andy-griffith-made-up-the-mayberry-diction-on-the-andy-griffith-show

"I thought Andy was making it up."

The Southern accents?

Andy Griffith coached his cast to speak with a North Carolina accent (https://www.metv.com/stories/andy-griffith-coached-his-cast-to-speak-with-a-north-carolina-accent)

Some of the actors were quicker to pick up on the drawl than others.

Andy Griffith coached his cast to speak with a North Carolina accent (https://www.metv.com/stories/andy-griffith-coached-his-cast-to-speak-with-a-north-carolina-accent)

Some of the actors were quicker to pick up on the drawl than others.

As someone pointed out, characters like Arnold never seemed to get the hang of the Southern accent.