I think in a case such as this style out rules substance. So cool sounding names is the way to go. In any case languages really only apply themselves to very small areas generally, most of the time countries share far more than one. Colonizing has always been a very human motivation and done since the beginning of recorded history so I'm sure we will see some interesting language spread. Especially if folks finish a map and move the same culture somewhere else and begin a new map (especially with the tunnelling node idea). I'd say no limits on having disparate sounding names on the same land area, it's better to explain it with story than it is to try and force an imposed idea of what we find natural.