That's true on Earth, but since English is generally the accepted universal language of space, science, and engineering, I think it's plausible for science fiction to depict it as the lingua franca of spacegoing humanity in the future.
It also helps that English is statistically dominant in many important ways:
In the Most Spoken Languages Stats counting __ language as their Primary / Secondary Language:
1) English has 1.452 Billion Speakers
2) Mandarin has 1.118 Billion Speakers
3) Hindi has 602.2 Million Speakers
4) Spanish has 548.3 Million Speakers
5) French has 274.1 million
6) Arabic has 274.0 million
In the # of Countries that recognize __ language as an official language:
1) English has 59 Countries that recognize it as a Official Language
2) French has 29 Countries that recognize it as a Official Language
3) Arabic has 22-25 Countries that recognize it as a Official Language
4) Spanish has 20 Countries that recognize it as a Official Language
5) Portuguese has 9-10 Countries that recognize it as a Official Language
6) German has 6 Countries that recognize it as a Official Language
To bring up another movie, Bulliet Train.
Was an asian book, with a wholy asian cast in the book. Yet for a few token characters, theres no asians in the movie. It got some heat for that.
Now, it was an awesome movie, Brad was really good in it, but it was brought up, why no asians? They could have set it up in Europe, on one of there trains, but they kept it in Japan.
A good quote from somebody was, well there are not that many asian super stars, well they said, You never LET asians be the stars in movies, so how can there be asian actors/actresses with name recognition, if you never let asians STAR in BIG movies??
Honestly most americans couldn't name but a few east asian actors/ actresses.
That's a Hollywood specific problem.
They have issues with casting Asian Actors/Actresses for __ reasons
Sure, that happens, but the problem being pointed out here is that it happens far too often -- we constantly see Asian characters in Trek with Western names, but only rarely see Asian characters with Asian names, and virtually never see Western characters with Asian names (unless you count Leila Kalomi, but that was an invented "exotic" surname that doesn't actually exist.) Nobody's saying it's impossible or wrong in the individual case, just that it's overused to a degree that feels like cultural erasure. If the Federation is as egalitarian as advertised, then we should see a less biased mix of name origins.
I've literally only met 1 person IRL that was White with a Chinese Last name.
My buddy married a Chinese gal and took her families last name so that their family name would live on.
His wife & in-laws was REALLY happy that their chinese family name lived on to the next generation.
They don't have to be. They just have to know enough to be able to communicate with their crewmates without requiring on machine translation. As I said, it's logical that there would be regular training in that, as with any other emergency procedure, and people would just have to be fluent in the aspects of the language relevant to their job.
Really, the idea that machine translation would be a perfect replacement for actually learning the language is as absurd as the idea that AI can replace screenwriters. At best, even translation done by humans is imperfect, since there are always conceptual differences that can't be literally translated from one language to another. So it's always going to be better to actually learn the language. Machine translation should just be an aid until you can do it yourself, not an excuse to be lazy and not even try to learn.
"Truer words were never spoken."
It was very, painfully obvious how badly Trek was doing representation to me right when Discovery came out, since The Expanse was still on the air as well.
One show tried to reflect "diversity" in the narrow sense that a liberal Californian would understand, meaning it just came across as "space America" - as was usually the case in the past. The other went out of its way to not only cast non-white people, but people with varied accents, mixed-race phenotypes, and characters who often had jarringly different first and last names, to drive home how much mixing had occurred over the centuries - and how America was a relatively minor component of future human culture.
The Expanse did "Diversity" FAR better IMO.