Different Tribes

I was wondering about the Celts that came from different regions.

Though I am well aware of their numerous tribes,

I was wondering what Celtic regions the three sisters represented or if they were mostly the same region, but representing three different social classes of Celts.

One Peasant, Bee Keeper.

One Noble woman ( Though she did claim to be a warrior.)

One trained Killer.

I was just abit lost cause they spoke in normal english accents and there was the Gaul ( French Celt.) whom had the bleeding arm, and this thick French accent ( Right at the beginning of the movie.) and what I beleive to be a Cael ( A Scottish Celt.) who had thick spikey red hair and lots of spiral motifs on his face. ( Inside a pub, halfway through the movie.)

I ask this because, the people who are basically English speaking or sounding, were Britons or Angles. Was there such a thing as British Celts. Forgive me if this sounds like a dumb question. Now that I think of it maybe they were pure Bristish tribes living in the english speaking region or maybe they were the Irish Regional celts who roamed across the England as well. ( Though it would seem more likely that these were the Caels.) I would love to know what name they have been given like the Caels and the Gauls.

I also understand that this movie is largely a parody and not to be taken seriously.