My starting point was the full list for Europe. From there I split off UK, then split off Scandanavia, then split off Southern Europe, then worked out a plausible split for the remaining western and eastern. For example, Czech fell into my eastern pile, but could have easily gone the other way...
I didn't even bother trying to bisect Africa or South America, as I couldn't find any evidence for such canonical bisections.
Political geography is tedious.