Welsh, people. Not Irish, not Celtic, not Scots. They are descended from the Welsh. How do I know this? The "strange" language/words they are speaking are WELSH. The old customs are WELSH. The laws are derived from OLD WELSH LAWS. Their society is set up as ancient Wales was, not with "Clans", but with individual "Kingdoms" (at one point, in post-Roman era Wales, there were 9 individual kingdoms: 3 major kingdoms, Gwynedd, Powys and Deheubarth, and 6 minor kingdoms.)

The show really isn't that unbelievable, IF you understand the history behind the Farrell "Kingdom/Queendom". So, instead of slamming that switch you do not understand, educate yourself.