Demosthenes' Hierarchy of Foreignness is a means of classifying how "alien" an individual is relative to a subject. It is organized in five tiers:
Utlanning are individuals who are of the same species as the subject, and are from a different region, city, or country.
Framlings are individuals who are recognized as being of the same species as the subject, but who are from another planet.
A raman is an individual recognized 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.
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.