The article is devoted to the problem of constructing a unifying identity through the commonality of language as an alternative to the concepts and practices most widely spread in the modern world, which are understood as the construction of a single ethnic identity (including the concepts of ethnonation and ethnonationalism), as well as the construction of general civil identity and "civil" nation. The primary attention is paid to the methodology of ethnology and social sciences in general, as well as to the scientific grounds and methods of the construction of a unifying identity through language. The evolution of methods of social sciences, changes in paradigms in ethnology, some linguistic theories in the problematic area of interdisciplinary research relevant to the issues of linguistic identity are considered. The international legal aspects of an ethnos are also considered; the inseparable connection between the phenomena of ethnicity, an ethnos and collective rights of an individual, on the one hand, and the phenomenon of native language and collective rights as one of the formats of existence and exercising personal rights and freedoms is postulated. The conclusion is made about the possibility, advantages, and potential social stability of the construction of a unifying identity that harmonises ethnic relationships through language identity.