Macedonian and Bulgarian are mutually intelligible but sometimes with some difficulty due to local dialects. Many elements of Macedonian have been influenced by BCS ( Bosnian , Croatian , and Serbian language) making it somewhat intelligble to BCS speakers more than Bulgarian. I am a BCS speaker and the Slavic languages ( in order) I mostly understand are as follows : Slovenian , Macedonian , Bulgarian , Slovak , Czech , Polish and then the eastern Slavic languages.