how do you 'accurately' speak English in ancient Rome?

IIRC Game of Thrones took a similar approach for noble families and the rabble of Lannisport, but leaned more heavily on northern accents for people from northern regions.

I don't recall American accents in Rome, but there may have been some in GoT. If the story is good and the acting and characterizations are top-notch, it doesn't matter IMHO.

Successful art doesn't have to be accurate. Successful entertainment even less so!

It's super telling that you get people essentially complaining about AAVE like it's an existential issue for the movie, but silence on any other anachronisms not related to race.

Denzel played a great Macbeth in the recent Joel Coen movie, despite not once being Scottish. Acting!

RP English has a certain perception in the US, but is it really the best accent in our times? The British Empire is gone, and did not rule the US. The American Empire, though hurtling fast toward extinction, is a sensible analogue. So some variety of American English seems fitting, and in general, an English language American movie will need to translate into American linguistic categories. For example, among Romans, you can vary dialects based on social class, ethnic origin, and so on.

But that's if you want analogical accuracy, and that kind of accuracy can work well when the subject matter of Rome is used as an occasion to critique our society.

I don't care. If the movie looks interesting to me I'll buy a ticket. You should do the same. Regular people spend way too much time and energy jumping into the pointless debates for no reason thinking they will fix everything, but only amplify the idiocy by giving it attention.

Rome was as much the dominant economic, cultural and military power of the ancient world as the US is of the present. I would actually prefer American accents being used in movies set in the Roman Empire.

So your show's in English but not set in England, what accent should you have? For quite a while, I'd have said "what native speakers from that area sound like when trying to speak English"...

But when I watched the HBO Chernobyl mini-series, they had a different approach. All the various Russian, Ukrainian, etc. accents were instead regional English accents. And that was pretty good, because, honestly, as someone who doesn't speak any Slavic languages, I can't easily tell the differences between them, and I'd miss the implicit cultural and social judgements the speakers make of each other. But I know exactly how an RP speaker looks down on an Estuary English speaker who in turn looks down on a Yorkshireman or Scotsman. By using my own country's accents, the narcissism of small differences comes through loud and clear.

The accompanying podcast said they did it to make the actors "act their roles and not their accents". But it is a balancing act - do you want the versimilitude of having people sound like they're from the place on-screen (while still speaking English)? Or do you want the nuances of language translated properly for you?

In purely fantasy worlds, there's no reason why elves speak RP, dwarves speak Scots and orcs speak Cockney... if anything, the dwarves should speak Old Norse!

On a final note, watch the British take the piss out of those self-serving Hollywood movies where they have Americans play the heroes despite their country not existing until several centuries later (and of course giving the baddies British accents): Jerry Brickhammer presents "The Crusades", the movie in honour of all the Americans who died in the early middle ages: https://www.youtube.com/watch?v=IbzlUQwaC4Q