How in the world do they speak English?!

Are you serious or a moron?

Assuming you are serious; the film is in English because it was made by English speakers. When shown in countries where English is not the dominant language, it was either dubbed or subtitled. As is standard for any movie. Movies made in Spain are in Spanish. films made in China are in Mandarin or Cantonese. And so forth.

Author of the Sodality Universe:
The Road fro Antioch
In the Markets of Tyre
Flight to Lystra
The Theater of Ephesus
The Council on Jerusalem (coming real soon now. In final edits.)

The Shattered World Series begins in 2025.

It might be hard to understand these days, but the original Star Wars was made on a cheaper budget and closer to an independent movie that wasn't expected to become a financial hit. So I don't think it would have crossed George Lucas mind to add the extra cost of hiring foreign actors speaking in a different language as he was already dealing with budgetary constraints while he was making Star Wars.

It's also a long time ago, not just in a galaxy far, far away. They had English first. So, the question you should really be asking is: what are the odds that we moved through old and middle English up to a modern English that sounds exactly like the dialect spoken by the citizens of the Republic and Empire?

Dude…any movie made for an English speaking audience needs to be in English (mostly, at least)….alien races…..ancient Romans..whatever….speak English…..if it’s made for China, speak Chinese….the medium works best when you are experiencing the words and language and understanding together

English did not originate on Earth. How about that ? lol

Questions like this are so fucking stupid they don't even need to be asked.

English is usually rated the most efficient language on Earth from over 7000 languages. It may be difficult to find a better language than English no matter what domain.