CT James Earl Jones = English accent?

Why do many people think that James Earl Jones has an English accent when he voices Darth Vader?
I've noticed this statement pretty often.

His accent seems to be more like a non-rhotic Southern US accent (JEJ is from Mississippi):

 

Jones has said he stuttered as a child, which is why he speaks slowly and deliberately. I've never noticed an accent.

 

I don't think he has a British accent at all. If I had to try and answer the question, I'd guess that since the other Imperials sounded British, folks just assumed Jones was trying to do the same.

 

Perhaps it’s his pronunciation of “Master.”

 

I think Jones speaks in a way that’s outside of regular accents as Darth Vader. Jones speaks in a deliberate enunciated manor that is well timed but also lyrical. That lyrical quality disguises accent. And his deep distinctive pitch also give Vader an other worldly quality. Add on top of that the breathing sound effect and whatever modulation is added to make Vader sound more mechanical.

What’s really interesting is when Hayden Christiansen adopts this same style of speaking after turning to the Dark Side. His line “You will try.” does an amazing job capturing the quality of Vader’s voice without other worldly mechanical additions. Hayden does an amazing job sounding like Vader and Jake Llyod.

 

I seem to recall reading an interview with Christensen shortly after the AOTC release, where he indeed said that a cross between Lloyd and Jones was exactly what he was going for.