I’ve been binge watching The Expanse via Prime, and am in Season 5 right now. I noted how one character seems to ‘switch accents’ between her presumably normal British-English accent, to that of a “Belter” accent when speaking with them. This, and this post got me thinking, just what is the accent of the Belters? With a lot of the hard-consonant emphasis, and some of the vowels’ pronunciation, I’m thinking . . . Dutch? German mixed with something else?
Tripler
Non-linguistics expert.
Jamaican + Afrikaans was always my guess, but it’s been awhile since I’ve seen the show.
The accent of the Belters is the accent of someone whose first language is Belter Creole.
As to the real-world basis of that language? Word of God says:
“Superstrate is English, substrates predominantly Chinese, Romance, Hindi Slavic, Bantu”
So English is the only Germanic language listed there.
I don’t think the Belter language or word pronunciation is derived from a particular source but rather is a pidgin with cognates from a mishmash of terrestrial languages. The language structure is clearly Germanic in form (probably for ease of understanding by the primarily English-speaking audience) and a number of the words are recognizable as being derived from some Germanic language (probably Danish or one of the Western Scandinavian languages), but there are also words that are Slavic, Japanese, Magyar, and of course a lot of basic English, which I assume is supposed to reflect the multicultural origins of Belter society. The accents vary between actors (I assume to reflect ‘regional’ differences between habitats) but they do seem to have a very Northern Germanic enunciation; if I were listening to dialogue without reference to the show I’d probably assume it to be Norse or Icelandic.
Stranger
Answers the mail–thank you!
Tripler
It wasn’t as clear as that from Firefly which had obvious sources.
The Belter culture is one of the coolest things about The Expanse.
I generally like the show but for me it was a toss up for what irritated me most: the Belter ‘accent’ or Avasarala’s constant hoarse mushing of language and terrible overacting.
Based on a lot of the Belter names in the books, I always assumed the Belt had a lot of Brazilians, and by extension Belter Creole has a hefty dose of Portuguese, along with English and a dozen other languages.
This site doesn’t really address the OP’s question, but it is adjacent. 
Now that’s cool. . . thanks @Retzbu_Tox!
@bump, are you able to pick out the individual Portuguese? I can’t tell, but I’m more biased towards what I thought was Danish/Nordic.
Tripler
Knowing the storyline, I now see why it’s a creole language.
It’s a creole, and based on some of the character names in the books and the Romance language aspect of the creole, I more or less assumed Brazilian origin for early Belt settlers.
Which ones did you think were particularly Brazilian?
Well, Diogo’s a Brazilian/Portuguese name, and I made the assumption that most Belt immigrants were probably not economically well off on Earth, so that would tend to point a little more toward Brazilians being the primary Romance language speakers vs. Spanish speakers in the early days of the Belt.
It’s not something well researched, just a sort of gut feeling lens that I viewed the Belt through while reading the books and watching the show.
But Harari is Jewish or Ethiopean. I’d be more inclined to pay attention to family names than first names.
I’d say there are as many sources for impoverished Spanish speakers as for Portuguese.
And if first names mattered, Camina is a Spanish name, not Portuguese.
I’m not saying I think there wouldn’t be a Brazilian influence, BTW, I’m sure there could be. But I didn’t really pick it up in books or TV, myself, so I was curious what you were basing it on.