ENThe author begins by defining the meaning of hypothetical modality, drawing on elements of the Petri net theory. Hypothetical modality is seen as a semantic category expressing the sender’s gradable attitude towards the story/situation being communicated. The author provides a paraphrase of a model sentence expressing hypothetical modality where the modal operator możliwe, że (perhaps) is a mandatory clement: Jan chyba czyta książkę. Perhaps John is reading a book. ‘the sender supposes that it is possible that Jan is reading a book at this moment’ Once hypothetical modality is recognised as a semantic category, the plethora of linguistic means employed to describe such senses hypothetical modality can be described. For this reason the author describes lexical, morphological, syntactic and mixed means (e.g. lexical and morphological) for the Lithuanian dialect spoken in the Punsk area (Poland). The linguistic means identified in the paper are categorised according to the degree of probability expressed. Further on, the author contrasts dialectical means in the Polish and Lithuanian languages, indicating similarities and differences between the dialect and the Polish and Lithuanian languages. In contrast with Lithuanian the author stresses the use of dialectical perfectum as an equivalent of Lithuanian modus relativus. In contrast with Polish, it is pointed to considerable formal similarity in the set of lexical characteristics as well as borrowings among lexemes and certain syntactic structures.