Slavs
Standardised Slavic languages that have official status in at least one country are: Belarusian, Bosnian, Bulgarian, Croatian, Czech, Macedonian, Montenegrin, Polish, Russian, Serbian, Slovak, Slovene, and Ukrainian.
Frano Supilo
On the major playground, Supilo becomes a supporter of a softer Yugoslavian unitarism (because of which he was often demonised in Croatian circles). Supilo's opinion (which was then shared by a large portion of Croatian and Serbian intelligence) had been that Croats and Serbs (to which he later added Slovenes as well) are one three - tribal people - therefore, not three tribes, even less three nations, but one Yugoslavian nation with three names. That, from the modern perspective an unusual idea, was a sign of the late national crystallisation on the Croatian side (in less parts Serbs and Slovenes - not to mention Macedonians and Montenegrins), as well as the territorial bubbles of Serbs and Croats, together with the fact Croatian and Serbian traditional languages have been exquisitely similar and inter - understandable on the conversational level. Practically, this has meant the creation of the Croato-Serb coalition, a creation by which the Serbs are recognised, de facto, as political people inside of Croatia, for the first time in history.