In this article, I explore the ways in which ethnic identity is expressed by following the formulaic socio-linguistic norm, the very method of which defies the authenticity of identity itself, thereby asserting the identity's multi-facetedness as sustained in performative linguistic practice. I look at multi-sited socio-linguistic interactions among Koreans in Japan, who claim their primary identity to be that of North Korea's overseas citizens even though none of them have North Korean passport or nationality. Their identity, in other words, is based on ideological commitment, which is in reality supported by their ongoing linguistic practice. A close look at their socio-linguistic life reveals their ethnicity's dual or multiple ontology, which challenges among other things the currently dominant assertion of Japanese self in the western academic discourse.