The map shows the areas where dialects of the Bulgaro-Macedonian dialect continuum are spoken: by a majority of speakers by a minority. Bulgarian and Macedonian, which together comprise the Eastern group of Southern Slavic, share a number of characteristics that set them apart from all other Slavic languages - such as the lack of cases, the post-fix article, lack of infinitive, formation of comparative forms of adjectives with the prefix "po-", and the existence of "preizkazno naklonenie (преизказно наклонение)", a verb tense used to convey information about events which the speaker didn't witness. On a local level there is no sharp boundary between Bulgarian and Macedonian dialects and the question whether Bulgarian and Macedonian are distinct languages or dialects of a single language cannot be resolved on a purely linguistic basis (see e.g. Chambers and Trudgill, Dialectology, Cambridge University Press (1998) or David Crystal. The Cambridge Encyclopedia of Language, 2nd ed. (2010)).