One has paid attention to ethnic groups living in Lithuania since olden times. However, one began to more widely discuss the problems of integration of ethnic minorities only after the Independence Restoration. One of the important problems of aliens' integration would be an absence of proficiency in the official language. It is the reason why the matter is examined more widely in this paper, the data of the performed investigation making it possible to examine and to compare the social, legal, cultutural, and integrational situation of ethnic-minority representatives who have mastered or not mastered the official language. During the investigation it has been revealed that the aliens who have mastered the official language have been living in Lithuania at least 20 years or have been born and brought up in this country. These persons freely express their abilities and rely on their forces; once having lost their jobs, most of the respondents would look for another job at State-owned institutions or companies. They take an active part in political life and in that of their national communities, observe the changes that take place in the national TV and newspapers, while believing that they have successfully integrated themselves into the Lithuanian State. The aliens who have not mastered the language believe that the principal reason that has affected their absence of proficiency in the language is a lacking communication environment. These representatives of national... [to full text]