Demosthenes' Hierarchy of Foreignness is a means of classifying how "alien" an individual is relative to a subject. It is organised in five tiers:
Utlanning are individuals who are of the same species as the subject, and are from a different region, city, or country. Culture is similar, communication between subject and Utlanning is generally easy.
Framlings are individuals who are recognised as being of the same species as the subject, but who are from another planet. Culture and manners between Framlings may be different, but they are still similiar.
A raman is an individual recognised as a sentient being who is of another species, but with whom communication is possible. In Speaker for the Dead and Xenocide, the Piggies and the Buggers are identified as raman.
The varelse are true aliens: they are sentient beings, but are so foreign that no meaningful communication is possible with the subject. Only war with Varelse is justified.
Djur are non-sentient beings. They are capable of independent thought and action, but their mode of communication cannot relay any meaningful information to the subject because the djur itself lacks the capacity for rational thought and self-awareness.