My 'Y-chromosome' male lineage and my MtDNA female lineage both signal celtic ancestry back to the original inhabitants of Britain. (As distinct from Anglo-Saxon, Viking, Norman, Roman or anything even more exotic).
My ancestors spoke the language which has now become Welsh. I speak English, an Anglo-Saxon invader language, because the celtic Britons of western England were defeated and assimilated. Perhaps it's time to look again at the language of my ancestors? - As I write, I have in front of me the book 'Speak Welsh' that I bought ages ago.
It reminds me of the American gibe about the second world war: "We're the reason you guys aren't speaking German."
The response is that you Americans are speaking German, a descendant of one of the Saxon Germanic languages spoken there in the dark ages. If the Britons had won, Americans would be speaking Welsh.
Next post: results of my DNA testing from Oxford Ancestors