What language do they speak?

[Tranquility]

Hey everyone, i was reading through Wicca, the complete craft, by DJ conway and where it said, this holiday is pronounced as so and so, what language is it that the celts spoke? Gaelic?
Any help would be great

[Eeluna]

The Celts were not comprised of a single nation of people, but were a group of loosely connected tribes that settled in many areas of Europe. They spoke different but similar languages. Two branches survive in some form today--Gaelic languages are still spoken in areas of Ireland, Scotland and Manx; Brythonic or Cymric survives in Welsh, in Breton and in Cornish.