The Celtic Languages used between 600 and 1600 include Welsh, Irish Gaelic, Scots Gaelic, Manx, Breton and Cornish. All of these languages belong to one of two Celtic groups, Brythonic and Goidelic. The Gaulish and Celtiberian language groups had both died out by this time, although Galatian was still spoken in Turkey until the fourth century.
The Goidelic languages developed in Ireland, and later split into Irish Gaelic, Scots Gaelic (with eastward migration) and Manx. This language group is also known as Q-Celtic because words in the Brythonic languages that begin with B or P begin with C or K in the Goidelic languages.