First contact with the nyarri only happened about 20 years before the current events of Tale of Inpherna (The 262nd year of the Age of Stars). Not much is known about their origins or how many nyarri colonies exist. The nyarri people you meet on Searadith are travelers from far away.
Most of what we know about the nyarri is from this painting of a traditional nyarri warrior running through a sandy desert. The painting was brought back from a far off world brought by a searadithian traveler.
The nyarri are more difficult to understand than most. It is not helped by their use of distinctive growls or purrs at the end of words to change their meaning. But the nyarri are also naturally guarded about the meaning of some of their words. And so a link of understanding from one novaborn to another cannot be made to quickly learn their language.
The nyarri are secretive creatures. They will gladly trade goods, music, art, and services with other species. However, knowledge about themselves, their people, and their technology are kept hidden.