Commonthroat, or one of its ancestors, was the principle language of the area around Newmans' Dale (The equatorial river basin where the yinrih first emerged) around the end of the Age of Decadence. As such, it was also the administrative language of the Bright Way.
It was already a prestige language throughout Focus when the secular government on Yih reasserted itself during the War of Dissolution, and was adopted by the newly formed Allied Worlds as their official standard language. Minority languages slowly died out among the Allied Worlds, although regional accents and substrate vocabulary remain.
Hearthside, not being an official AW member state, retains a distinct language, although nearly all its citizens are also proficient in Commonthroat. Moonlitter and Partisan territory likewise share a distinct language, with separate varieties used by each polity. L2 Commonthroat speakers are as abundant on Moonlitter as on Hearthside, but most residents of Partisan Territory are monolingual.
The Spacer Confederacy does not have an official language, in keeping with its hyper libertarian tendencies, but Commonthroat is the de facto lingua franca, and is used by the Federal Council and Federal Police. In fact, there are several city-states within the Confederacy that have developed and speak conlangs unique to them alone in an effort to further assert their independence.
Wayfarer's Haven, being an SC city-state formed by refugees from Moonlitter, speaks a variety of Commonthroat heavily influenced by the language of Moonlitter. Iris, Lodestar, Stormlight, and Pascal all have Moonlitter accents, while Sunshine speaks with a Hearthsider accent, and Tod has a Welkinstead Moony accent.
The
Split Horizon, another SC city-state, and the first Human settlement at Focus, speaks English.
I've been thinking of developing a relex of Commonthroat mapped to Human-pronounceable speech sounds called Monkey Fox Pidgin (or
) that would be spoken by Human residents of Focus. Probably won't get around to it, but it's still rattling around in my head.