Just for reference, folks, "Celtic" is pronounced with a hard C, not the soft C.
Gaelic (at least Irish) doesn't have a K, so C is always hard and S is, well, S.
Does this mean...? Yes, they're not the Boston (pron) "Seltics". They are the (pron) "Celtics".
BTW - an interesting book about the Celts and Irish in particular is Dennis Cahill's "How the Irish Saved Civilization".
Merry Christmas.
Thanks, I'm still trying to get through Henri Hubert's book, The History Of The Celtic People.