Abstract: The subject of the research is the attitude of married couples living in the cities of the Mari El Republic towards the Mari language, the place of the Mari language in the communication and values system of an urban family. The problem set by the authors is viewed taking into account the ethnofactor opposition between a mononational Mari family when both spouces identify themselves as Mari and multicultural family when one of the spouces of Mari and the other is Russian. The rationale of the research is caused by the need to study the modern sociolinguistic situation in polyethnic Russian Federation constituents and to define the role of national (regional) dialects. The research is based on the sociolinguistic data obtained in 2012 by the sociological department of Vasiliev Mari Research Institute of Language, Literature and History as a result of the survey dedicated to the topic 'The Language Situation in the Mari El Republic'. The research methods include statistical analysis, systematisation, analysis and generalisation. The author has also used the sociological tools such as random non-repetition quote sample, standard inteview, etc. The scientific novelty of the research is caused, first of all, by the empirical material that is introduced to the academic community for the first tijme, and, secondly, by the problems raised by the authors (communicative and values role of the Mari language in the minds of a modern urban family) that is viewed from the point of view of regional ethnosocial and sociolinguistic studies. The authors focus on the following questions that allow to define the attitude of spouces in the aforesaid two types of married urban couples towards the Mari language: recognition/denial of Mari as a native language, competence in Mari, concerns about the future of the Mari language, attitude to the status of the Mari language and its functions in the society, and prospects for developing Mari as a state language. The authors of the article prove the fact that mononational and multinational families have very different attitudes to the Mari language. Multicultural families tend to deny the ethnic importance of Mari which creates opportunities for their further language assimilation.