Aside the fact you have linked to a declaration linked to political platform initiatives, one of the core serbian propaganda machinery during the 90's wars and

Aside the fact you have linked to a declaration linked to political platform initiatives, one of the core serbian propaganda machinery during the 90's wars and breakup of Yugoslavia was denying identities and right for self-determinism across constitutive nations in said country. Prime example was (and is) throughout denial of montenegrin nationality and language, the other (among many) establishing a never in history existing one (not common base) language platform which would solidify serbian tendencies to tie-in languages and outside of its area, and thus people, into its own agenda. Our children, at least in Croatia, have trouble understanding a large volume of lexicography from swrbian language, and I am sure there's the opposite as well. Notable is the absence of Bulgarian in the story, which to a large extend is also understood by our yugoslavian-schooled peers, no different than macedonian or slovenian for that matter. Any and all discussion around languages in these matters have started and stopped by politics and ultimately even supported by academia. Is there a common understanding and overlap between languages? Of course. Are there differences? Of course, and as time goes by they grow larger - new generations have no idea what the other one are talking about for a lot of even trivial examples. Whomevwr says differently either does not love in the region or lives in a bubble. Whether that's anecdotal or a docimented fact (exercise to a reader to find reactions in each country to said declaration that followed promplty lole fire from all levels from academia to politics in all countries) is a sideshow to the following: apart from yugoslavian period and a bit before there's no shared history (500+ years of ottoman empire does that to one part of the region whereas the other wasn't in it), there's no shared literature throughout history (since it's a wikipedia post, find history of croatian literature and then serbian), how come it's called serbo-croatian or croato-serbian excluding all other nationalities/countries (and how come it's only ex-yugoslavia centric?), and ultimately and the only unarguable reason relevant to the topic is that language is one of the key components to national identities which region has struggled (wars over) within recent decades - tha ultimate reason why this won't happen ever, as exemplified even by this small universe of replies within.. which was my whole point.