Ethnogenesis
Ethnogenesis (from Greek ethnos ἔθνος, "group of people, nation", and genesis γένεσις, "beginning, coming into being"; plural ethnogeneses) is a process in which a group of people acquire an ethnicity, that is, a group identity that identifies them as a cultural group. This can originate through a process of self-identification as well as come about as the result of outside identification.
Passive or active ethnogenesis
Ethnogenesis can occur passively, in the accumulation of markers of group identity forged through interaction with the physical environment, cultural and religious divisions between sections of a society, migrations and other processes, for which ethnic subdivision is an unintended outcome. It can occur actively, as persons deliberately and directly 'engineer' separate identities to attempt to solve a political problem – the preservation or imposition of certain cultural values, power relations, etc. Since the late eighteenth century, such attempts have often been related to language revival or creation of a new language, in what eventually becomes a "national literature".