What Brittonic dialect was spoken in the kingdom who had the father of Owain mab Urien as king?
Owain mab Urien Owain mab Urien (or Owein) (died c. 595) was the son of Urien, king of Rheged c. 590, and fought with his father against the Angles of Bernicia. The historical figure of Owain became incorporated into the Arthurian cycle of legends where he is also known as Ywain, Yvain, Ewain or Uwain. In his legendary guise he is the main character in Chrétien de Troyes's "Yvain, the Knight of the Lion" and the Welsh Romance "Owain, or the Lady of the Fountain", which corresponds to Chrétien's poem.
West Saxon dialect West Saxon was one of four distinct dialects of Old English. The three others were Kentish, Mercian and Northumbrian (the latter two were similar and are known as the Anglian dialects). West Saxon was the language of the kingdom of Wessex, and was the basis for successive widely used literary forms of Old English: the Early West Saxon of Alfred the Great's time, and the Late West Saxon of the late 10th and 11th centuries.