>>4241330>Russian is my top choicethat would probably be everyone's top choice because there is more Russians than all other slavs combined. Polish is also good choice, there is like 40M of them and are one of most propulsive economies in EU, i see them achieving great things in 20 or so years
>Also considering Polish, Czech, and Serbian/Croatian.Czech is good choice because you can get around in Czech republic and also in Slovakia, a lot of Slovaks are fluent in czech. In that regard, i will answer to next part of your question, which one hs the highest degree of mutual intelligibility. About BCMS (bosniak-croatian-montenegrin-serbian), politically correct name for one main south slavic language with regional differences, well, there is more of us than Czechs and Slovaks, but less than Poles and eastern slavs. Funny thing is you can, by knowing BCMS, get around in 4 countries (Bosnia, Croatia, Montenegro, Serbia), and there are high chances you'll be understood in Slovenia and Macedonia as well. A lot of people
in those 2 countries can, if not speak, at least understand "our" language. So basically, by knowing croatian you can get around in 6 countries
>Which one has the highest degree of mutual intelligibility or at least makes learning others the easiest?I'd say its slovak, because Slovakia is literally in the middle of Slavic countries. There is Czech rep to the west, Poland to the north, Belarus and Ukraine to the east and balkan slavs to the south (even though there are Hungary and Austria between Slovakia and south slavs)
