EN
The aim of this paper is to present the issues related to examining the frequency of linguistic characteristics as one of important determinants constituting a given language variant. The signifi cance of the frequency of linguistic phenomena as a factor differentiating the north borderland Polish language in Lithuania is discussed on the example of Polish dialects used in the areas of Ignalina and Zarasai. This region, which is a narrow strip running along the Lithuanian-Belarusian and Lithuanian-Latvian borders, considered the third most dense Polish-speaking area in Lithuania, constitutes only a part of the former Polish enclave, which is currently divided between three countries: Lithuania, Latvia and Belarus. The issues are presented on the example of the realisation of unstressed o, particle czy and forms of the 1st person singular of the past tense. The basis for the analysis was the text corpus containing 117,446 textual words (ca. 200 pages of a computer script of the recordings of 50 informers from 40 locations from the periods 2000-2001 and 2010-2011).