Rather than continuously adding to the OP, I’m going to post replies. Feel free to comment either on the root of the thread or as a reply to a specific comment.

Here’s a geopolitical map of Focus, the yinrih’s home star system. As is conventional in a lot of sci-fi, the name of the star can serve as the name of the whole system. Humanity’s home system is referred to as Sol.

Random Facts about Each Body:

Focus

The Bright Way refers to a star hosting sapient life, especially their own, as a hearth star (not to be confused with a star hearth). All yinrih languages have a simple word for sun, but since humans can’t utter vulpithecine speech sounds we decided to give their star a nice classical name. The Latin word focus means hearth, and a star serves as one of the foci of an elliptical orbit, so the word seemed fitting all things considered.

Hearthside

The closest planet to Focus, Hearthside is tidally locked. The region around the substellar point is called The Nightless Desert. The capital city, located directly on the substellar point, is known as the City of Eternal Noon. There is a green belt running along the terminator. The City of Eternal Noon is the center of religious government of the Bright Way. Politically the planet is an ecclesiocratic republic, economically it is destributist (respecting private property while being aggressively anti-corporate). Companies must either be privately owned or cooperatives. There is no public stock market, and citizens are forbidden from holding a stake in a foreign company. Hearthside retains a unique language, but most citizens are proficient Commonthroat speakers as well.

Sweetwater

An ocean planet, Sweetwater is the innermost member of the Allied Worlds. It’s famous for its class disparity. There is a wealthy upper class living in underwater cities, and an underclass of surface-dwellers in roving ships and submarines. Some make a living fishing or mining, while others are pirates. There are a few small fixed islands, but there are also free-floating rafts of vegetation large and dense enough to support entire forests. These mobile islands have no fixed topography, and undulate along with the waves. As such it is nearly impossible to build fixed structures on them, and they are very popular with Atavists and others who seek to live a primitive lifestyle.

Yih

The cradle of the yinrih species, and one of only two planets in the galaxy to naturally give rise to life. The planet is the center of political power of the Allied Worlds. It is also the urheimat of the Commonthroat language. After the formation of the Allied Worlds, regional languages were slowly supplanted by Commonthroat across the AW, but substrate vocabulary remains.

Newhome

The first planet to be terraformed. The first wave of colonists started a machine-worshiping cult.

Welkinstead

The first of the two gas giants (or if you want to be pedantic, the only gas giant with Moonlitter being an ice giant). There are floating cities in the upper atmosphere that mine and refine economically exploitable gasses. There are also a few moons, and their inhabitants, called moonies, are seen as rustic and uncultured. The moony accent of Commonthroat carries many of the same stereotypes as the Southern American accent.

The Inner Belt

The first of the two asteroid belts, and home of the Spacer Confederacy. The SC is a less a unified polity and more a very loose collection of independent city states that group together solely to defend their sovereignty against bigger players. These city-states take the form of orbital colonies that go from asteroid to asteroid mining and selling the minerals in order to keep the lights on. One of these city-states is Wayfarers’ Haven, which started out as a refugee camp of Moonlitter citizens fleeing a Partisan border expansion. The Dewfall departs from Wayfarers’ Haven, making the tiny colony the first nonhuman polity to have diplomatic relations with Earth.

Moonlitter

An ice giant with many moons. Moonlitter is caught in the middle of the cold war between the AW and the Partisans. Its government is notoriously unstable, as both the AW and the Partisans fight for the hearts and minds of its citizens. Border skirmishes between Moonlitter and the Partisans are common. When Moonlitter allowed Welkinstead to establish a military outpost near their border, the Partisans retaliated by glassing the dwarf planet Pilgrims’ Rest. Fortunately the AW peacekeepers evacuated the residents to the inner belt before their home was destroyed, which is how Wayfarers’ Haven was founded.

The Outer Belt

A resource-rich region politically divided between Moonlitter and Partisan Territory. Both polities share a common language, Outlander, but the Partisan dialect is much more conservative thanks to government efforts to stave of encroachment of Allied Worlds media and with it the spread of Commonthroat.