@Sviatogor I looked at the actual lexical distance matrices from that study you cited. Thats why I said who can understand those trees, they love to post impressive looking graphs in studies to make it look official and even they wouldnt know how to interpret a tree like that from just looking at it. From the distance matrices polish isnt closer to eastern slavic languages in their study. Slovak actually has higher lexical similarity with belarusian than polish does in that study. Ukrainian and slovak and polish are the same distance while polish was slightly closer to literary Russian.