People with warp travel and a high tech, computerized society say things like "The day of lightning", "the trial of strength", or "the forbidden land". In short they typically end up sounding like Native Americans, or more accurately, what white people think Native Americans sound like and wrote dialog for in spaghetti westerns.
Speaking a polyglot language like English tends to distort one's perspective. We simply don't notice when we use words and phrases that are pretty much exactly like that.
I mean, on the Day of the Thunder God, I got a call on my hears-far in the middle of watching my sees-far, and had to get in my moves-by-itself to head to The Place Below The City. I traveled on the Road Between Estates to the almost-island, and spoke to One Who Knows The Word Of Water at the All-Together in the High Woods about the Balance of Eating-Away.
Which is exactly the same thing as saying "On Thursday, I got a call on my telephone in the middle of watching television, and had to get in my automobile to head to the suburbs. I traveled on the interstate to the peninsula, and spoke to a hydrological scientist at the University in Palo Alto about the equilibrium of erosion."
And if I spoke Spanish, Greek, or Latin, that sentence would sound as much like the first version as the second.
So, basically, English sounds more "sophisticated" to an Anglophone because it's chock full of foreign words whos meanings we either don't know or don't really hear.
Incidentally, I've never understood the assumption that people in Sci Fi shows were actually supposed to be speaking English. Nobody ever makes that assumption when they're watching something set in, say, 17th Century France or Pharaonic Egypt. On Star Trek, they might be speaking Esperanto, or some kind of interlac of Terran, Vulcan, and other languages. We're just watching a translation into our Primitive 20th-Century Dialect.