I am not sure if culture is the right term.
But the internet, programming languages and especially global gaming certainly is English. You do not speak/write with players all over the world in Spanish or Chinese. You use English.
The #1 language is broken English.
But maybe culture is the right word after all, if you consider developer teams that are also from all over the world. Unless they share a language by coincidence, the project language is bound to be English. I mean, English native is probably a minority on Itch in general. The other post mentioned only 30% traffic from US. And I count at least 4 non native English speakers in this thread alone. All writing in English.
Translating into (bad) English is something most developers would be able to handle without helpers.