Perfume

With the exception of healers, yinrih don't wear clothes. While they do use things like backpacks and pocketed leg bands, the communicative function of clothing is filled by perfumes.

Yinrih produce pheromones, both as an ambient musk and via their ink, that other yinrih can use to gain information about them. Approximate age, gender, emotional state, and whether or not one is currently in a childermoot can be determined readily by these natural odors.

Artificial perfumes are an extension of this form of olfactory communication. Perfumes communicate things like occupation, social status, and rank. This can get surprisingly detailed. Different military ranks use different scents, managers and floor staff at stores have their own odors, and hearthkeepers have different perfumes that serve as clerical vestments.

Perfumes are sometimes used to advertise stores, assuming the store's wares don't have a unique smell of their own, such as the rubber and grease smell of a hardware store or the smell of organic solvents common to electronics stores.

The good news for humans is that yinrih olfactory tastes largely overlap with ours, so most yinrih perfumes smell pleasant, if a little unorthodox. Clerical perfume, for example, smells like the faint note of cigarette smoke that has permeated the walls of a Motel 6 from the 90s. Perfumes used by veterans like Tod smells like the sulfury discharge of fireworks or model rocket engines. While healers use their lack of fur as the big indicator of their occupation, there is also a traditional scent used by healers that smells like lavender. While these perfumes can be smelled at a distance by other yinrih thanks to their ridiculously powerful noses, humans only catch a whiff now and then because yinrih don't use the same amount as a human would.

While not very common, some machine indicators use olfactory signals rather than lights or sounds to indicate warnings or states of operation.